The preferences, experience and level of

comfort of anaesthetists in managing difficult

intubation and ‘cannot intubate, cannot

ventilate’ scenarios

Lize Buitenweg

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of

Medicine in Anaesthesiology. Johannesburg, 2016.

i

Declaration

I, Lize Buitenweg, declare that this research is my own work. It is submitted for the

admission to the degree of Master of Medicine in Anaesthesiology in the University of the

Witwatersrand, Johannesburg. It has not been submitted before for any degree or

examination at this or any other university.

___________________

11th day of April 2016

ii

Abstract

Background: The “cannot intubate cannot ventilate” (CICV) scenario is a rare occurrence but

can lead to significant morbidity and mortality if not managed appropriately. International

data shows that anaesthetists lack knowledge of and fail to employ difficult airway

algorithms.

Method: A prospective, contextual, descriptive study was done to determine the

preferences, experience and level of comfort of anaesthetists in the Wits Department of

Anaesthesiology to manage difficult intubations and CICV situations. A previously validated

questionnaire was adapted for local use and distributed to all available anaesthetists.

Results: A total of 111 (88.1%) participants knew the location of the difficult airway trolley,

but 43 (38.8%) stated that the trolley is not easily accessible.

Ninety two (73%) participants preferred the videolaryngoscope as first choice device when

facing a difficult airway. The predominant second choice devices were the flexible fibre-

optic scope, chosen by 52 (43%) and the intubating laryngeal mask, chosen by 48 (38.1%).

The majority of participants had no experience with the retrograde wire set, optical stylet

and rigid bronchoscope.

The most popular device for cricothyroidotomy, chosen by 47 (37.3%), was an IV cannula,

but only 34.9% was comfortable with using this option. The majority of anaesthetists have

no experience with the internationally recommended open surgical method. Sixty-three

(50%) of the participants have experienced a CICV scenario in clinical practice.

Conclusion: Airway training can be improved in our department. The location of the

difficult airway trolley is not known by everyone and many believe that it is not readily

available in an emergency. The videolaryngoscope is the preferred difficult airway device

and the IV cannula the first choice in a CICV scenario. There is a significant difference in the

comfort level of consultants and registrars with the use of most advanced airway devices.

iii

Acknowledgements

I would like to thank the following people:

Helen Perrie and Juan Scribante for their constant guidance and tremendous support.

Professor Analee Milner for her advice and invaluable input.

Wong et al for the use of their questionnaire and permission to adapt it for my study.

My husband and other family members for their support and patience throughout the

process.

iv

List of figures

Figure 2.1 The airway management funnel of the Vortex model 17

Figure 2.2 The overhead view of the funnel of the Vortex model 17

Figure 2.3 Anterior midline structures in the neck 31

Figure 4.1 Overall knowledge of location of the difficult airway trolley 45

Figure 4.2 Device preferences for managing a difficult airway 46

Figure 4.3 Preferences when managing a CICV scenario 47

Figure 4.4 Participants comfortable with different airway devices used for

difficult airway scenario

48

Figure 4.5 Participants uncomfortable with different airway devices used

for difficult airway scenarios

49

Figure 4.6 Participants comfortable with equipment used for

cricothyroidotomy/surgical airway in CICV scenario

51

Figure 4.7 Participants uncomfortable with equipment used for

cricothyroidotomy/surgical airway in CICV scenario

51

v

List of tables

Table 4.1 Demographics of participants 44

Table 4.2 Knowledge of the location of the difficult airway trolley at

different hospitals

46

Table 4.3 Experience of anaesthetists with different airway devices used

for difficult airway scenarios

48

Table 4.4 Comparison of the level of comfort of consultants vs

registrars/MO’s with the use of different airway devices

49

Table 4.5 Experience of CICV scenario 50

Table 4.6 Experience of anaesthetists with different airway devices used

for CICV scenarios

50

Table 4.7 Comparison of the level of comfort of consultants vs

registrars/MO’s with the use of different airway devices

52

vi

List of abbreviations

ASA American Society of Anaesthesiologists

CAFG Canadian Airway Focus Group

CHBAH Chris Hani Baragwanath Academic Hospital

CICV Cannot intubate, cannot ventilate

cLMA™ Classic Laryngeal Mask Airway

CMJAH Charlotte Maxeke Johannesburg Academic Hospital

DAS Difficult Airway Society

GEM Gum elastic bougie

HJH Helen Joseph Hospital

ICU Intensive Care Unit

ILMA™ Intubating Laryngeal Mask Airway

LMA™ Laryngeal Mask Airway

LT™ Laryngeal Tube

LTS™ Laryngeal Tube Suction

NAP4 Fourth National Audit Project of the Royal College of Anaesthetists and the

Difficult Airway Society

PCK™ Portex Cricothyroidotomy Kit

PLMA™ ProSeal Laryngeal Mask Airway

RMMCH Rahima Moosa Mother and Child Hospital

SASA South African Society of Anaesthesiologists

SAD Supra-glottic airway device

SLMA™ Supreme Laryngeal Mask Airway

UK United Kingdom

WDGMC Wits Donald Gordon Medical Centre

1

CHAPTER 1: Overview of the study

1.1 Introduction

This chapter is a brief overview of the study and includes the background of the study, the

problem statement, the aim and objectives, as well as the research assumptions,

demarcation of the study field, research methodology, significance of the study, research

report outline and a summary.

1.2 Background

The “cannot intubate cannot ventilate” (CICV) scenario is a rare but serious occurrence in

anaesthetic practise (1, 2), as illustrated by the case of Elaine Bromiley in the United

Kingdom (UK) in 2005 (3). Anaesthetists generally have the necessary expertise to evaluate

and predict difficult airways. This prediction is however not always accurate and

unanticipated difficulties may arise. A simulation study done in a large teaching hospital in

Glasgow, UK (4) demonstrated that the majority of anaesthetists and anaesthetic assistants

are not well prepared for a CICV situation. Almost two-thirds of the participants in the study

could not even locate the equipment needed to manage a difficult or failed intubation.

Several different guidelines have been published by various anaesthetic societies on how to

manage the anticipated and unanticipated difficult airway (2, 5-8). The guidelines of the

American Society of Anaesthesiologists (ASA) Task Force on the Management of the Difficult

Airway were initially published as a result of the numerous peri-operative adverse events

related to airway management. These guidelines are not simple to follow but offer a variety

of options depending on the skills and preferences of the anaesthetist (9). In 2004, the

Difficult Airway Society (DAS) from the UK published guidelines for the management of the

unanticipated difficult intubation, of which an update was published in 2015 (7, 10). These

guidelines have a sequence of flow-charts in which the authors suggest the use of back-up

plans if the initial plan fails (7, 10). Similar guidelines have been published by the Canadian

Airway Focus Group (CAFG) (11).

Established protocols help ensure that time critical management options are not ignored or

delayed in emergency situations. Observation has however shown that adherence to these

2

protocols may be compromised in circumstances with high stress and time pressures. The

“Vortex” approach was devised in 2008 by Australian anaesthetist Nicholas Chrimes. This

approach uses an uncomplicated “cognitive aid”, instead of the progression through a

complicated algorithm. (2)

The South African Society of Anaesthesiologists (SASA) is the professional body for

anaesthetists practising in South Africa. In 2008 they published recommendations for South

African hospitals and clinics on suggested airway management resources in operating

theatres. These guidelines include suggestions on airway assessment as well as necessary

routine and emergency airway equipment required in the different settings. An update of

these guidelines was published in 2014. (12)

In unanticipated difficult airway situations, early insertion of a supraglottic airway device

(SAD) is now standard practice, as long as the patient has adequate mouth opening. The

specific SAD chosen should be one that the anaesthetist is familiar with and that is easy to

insert. While SADs are often effective, success cannot be guaranteed. (13)

The respective difficult airway guidelines all end with the CICV scenario, recommending

either a needle or surgical cricothyroidotomy as the next step (2, 7, 9, 10). In an ASA Closed

Claims Analysis of the 179 claims for difficult airway management from 1985 to 1999, the

authors found that repeated intubation attempts were related to an outcome of death or

brain damage in claims where a perioperative CICV emergency developed (14). It can be

assumed that the anaesthetists involved in these claims did not manage to secure a surgical

airway timeously.

Klein (15) emphasises the significance of prior experience in the development of skills for

use in acute situations. It has been shown that proficiency in cricothyroidotomy

performance requires repeated practice and a clear mental algorithm instead of episodic

past experience (1).

1.3 Problem statement

The CICV scenario is a rare occurrence but can lead to significant morbidity and mortality if

not managed appropriately (2, 16). It has been shown internationally that anaesthetists

generally lack knowledge of difficult airway algorithms or fail to employ them in emergency

3

situations (4). Although many advances have been made in airway management, adverse

respiratory events still form a large part of malpractice claims (14, 17, 18). Medical officers

and registrars working in the Department of Anaesthesiology at the University of the

Witwatersrand (Wits) are occasionally in a situation where help from a senior anaesthetist is

not immediately available, should an airway emergency present itself. The preferences,

experience and level of comfort of anaesthetists in this department to manage difficult

intubations and CICV situations and use available airway adjuncts are not known.

1.4 Aim and objectives

1.4.1 Aim

The aim of the study was to describe the preferences, experience and level of comfort of

anaesthetists in the Wits Department of Anaesthesiology in managing difficult intubation

and CICV scenarios.

1.4.2 Objectives

The objectives of this study were to:

describe the knowledge of anaesthetists regarding the location of the “difficult

airway trolley” in the various hospitals affiliated to Wits;

describe the preferences of anaesthetists with different airway devices and

techniques when faced with a difficult intubation or CICV scenario; and

describe the experience and comfort level of anaesthetists when managing a difficult

airway or CICV scenario.

1.5 Research assumptions

The following definitions will be used in the study.

Anaesthetist: is a qualified doctor working in the Department of Anaesthesiology including

medical officers, registrars and consultants.

Medical officer: is a qualified doctor practising in the Department of Anaesthesiology under

specialist supervision. Medical officers with more than 10 years of experience are career

medical officers and are regarded as consultants.

4

Registrar: is a qualified doctor who is registered with the Health Professions Council of

South Africa as a trainee anaesthetist.

Consultant: is an anaesthesiologist who has completed all criteria and passed the required

South African College of Medicine examinations, or equivalent. They are regarded as

specialists in the field. Career medical officers are in included in this definition.

Difficult airway: for this study, a difficult airway will refer to a scenario where the

anaesthetist involved has difficulty with either mask ventilation, laryngoscopic view of the

vocal cords and/or intubation of the trachea.

CICV scenario: refers to the “cannot intubate, cannot ventilate” situation. This is an

emergency situation in which the anaesthetist fails to secure the patient’s airway and is

unable to deliver oxygen to the patient’s lungs.

1.6 Demarcation of study field

The study was conducted in the Department of Anaesthesiology, affiliated to the Faculty of

Health Sciences of the University of the Witwatersrand. The associated hospitals include

Chris Hani Baragwanath Academic Hospital (CHBAH), Charlotte Maxeke Johannesburg

Academic Hospital (CMJAH), Helen Joseph Hospital (HJH), Rahima Moosa Mother and Child

Hospital (RMMCH) and the Wits Donald Gordon Medical Centre (WDGMC).

The Department of Anaesthesiology consists of 208 anaesthetists, including 22 medical

officers, 112 registrars and 74 consultants.

1.7 Research methodology

A prospective, contextual, descriptive research design was followed in this study. The study

population consisted of anaesthetists working in the Department of Anaesthesiology. In this

study a convenience sampling method was used, questionnaires were distributed to all the

accessible anaesthetists working in the Wits Department of Anaesthesiology. Inclusion and

exclusion criteria were defined.

5

An extensive review of the literature was done and a questionnaire developed by Wong et

al (16) in 2005 was identified as appropriate for the study. The questionnaire was adapted

for local use and validated by four airway management experts in the Department of

Anaesthesiology.

Data was collected by distributing questionnaires at academic meetings at the various

hospitals as well as at combined departmental meetings, during the months of June to

December 2015. Approval to conduct this study was obtained from the relevant authorities.

This study was conducted according to the principles of the Declaration of Helsinki (19) and

the South African Guidelines for Good Clinical Practice (20). Several measures were taken to

ensure the validity and reliability of the study.

Data was captured onto spread sheets using Microsoft Excel® 2010 and analysed using

GraphPad InStat® in consultation with a bio-statistician. Descriptive and inferential statistics

were used.

1.8 Significance of the study

The CICV situation is a rare but serious occurrence in the practice of anaesthesia that has

devastating consequences if not managed appropriately (2, 16). It has been shown

internationally that anaesthetists generally lack knowledge and skill to manage CICV

scenarios (4). It is therefore of paramount importance to determine whether anaesthetists

working in the Department of Anaesthesiology are comfortable in managing unanticipated

difficult airway and CICV scenarios. If the results of this study reveal that there is lack of

experience and comfort in managing difficult airway and CICV scenarios, it may contribute

to the development of an ongoing departmental educational programme.

1.9 Research report outline

The report will be discussed as follows:

Chapter 1: Overview of the study

Chapter 2: Literature review

Chapter 3: Research methodology

Chapter 4: Results and discussion

Chapter 5: Summary, limitations, recommendations and conclusion.

6

1.10 Summary

This chapter provided a brief overview of the study. Chapter 2, the literature review,

follows.

7

CHAPTER 2: Literature review

2.1 Introduction

In 2005, an anonymous independent report on the death of Elaine Bromiley was prepared

by Professor Michael Harmer (Professor of Anaesthetics and Intensive Care Medicine at the

Wales College of Medicine, Cardiff) and published with permission of her husband, Martin

Bromiley, for learning purposes. (3)

Elaine Bromiley was a 37 year old female who presented for routine endoscopic sinus

surgery and septoplasty on 29 March 2005 at a well-staffed and well-equipped clinic. During

the pre-operative assessment, done by a consultant anaesthetist, the only findings of note

on history and physical examination were congenitally fused vertebrae in her neck and

“slightly restricted neck movements”. This however was noted not to be a problem during

previous general anaesthetics. (3)

After induction of anaesthesia, the involved anaesthetist’s airway plan was to insert a

laryngeal mask airway (LMA™), but this technique failed, which was perceived to be as a

result of inadequate depth of anaesthesia. An additional dose of the induction agent was

administered but the anaesthetist was still not able to insert the LMA™ or to inflate the

lungs with bag mask ventilation. At this stage, the patient’s oxygen saturation started to

deteriorate and her heart rate started dropping. The anaesthetist then proceeded to

attempt tracheal intubation after giving a dose of atropine to treat the bradycardia and

suxamethonium, but was unable to visualise the larynx. He was then faced with the CICV

scenario and a second consultant anaesthetist was called to assist. (3)

Up to this point, the actions of the involved doctors were thought to be appropriate and in

keeping with acceptable practise, but their subsequent management of the CICV scenario

did not follow prescribed practice guidelines. For twenty minutes after the patient first

became hypoxic, the anaesthetists persevered in trying to intubate the trachea, using

different methods and adjuncts. Even with a qualified ear, nose and throat surgeon in

theatre, they did not attempt a surgical airway. After insertion of an intubating laryngeal

mask airway, they were able to improve her oxygen saturation to 90%, but continued with

attempts at tracheal intubation through the LMA™, which were unsuccessful and led to

8

further desaturation. Only at this stage did they decide to abandon the procedure and allow

the patient to wake up. The LMA™ was removed, an oral airway was inserted and the

patient was taken to the recovery room once it was established that she was breathing

adequately. She did however not regain consciousness and was later admitted to the

intensive care unit where a definitive airway was established. She had suffered severe

hypoxic brain damage and was taken off ventilatory support a week later and subsequently

demised. (3)

During an interview with the involved anaesthetist, it was established that he did not keep

track of time. He said that had he been aware of how much time had passed, he would have

performed a surgical airway much sooner. This anaesthetist has been described by his

colleagues as “a very diligent and caring doctor who practices careful anaesthesia”. (3)

This untimely death of a young, healthy mother of two young children, is just one example

of how even experienced anaesthetists can be ill prepared and poorly trained to manage a

CICV situation, with devastating consequences.

2.2 Pathophysiology of hypoxia

Hypoxia as a result of airway complications and failure to ventilate, has deleterious effects

on the structure and function of essential organs, especially the heart and the brain. The

high energy requirements in relation to the low energy reserves of neural tissue, make the

brain particularly susceptible to hypoxia. Even though the brain makes up only 2% of total

body weight, it is responsible for 20% of oxygen consumption. Under normal physiological

circumstances, the higher demand for oxygen leads to a proportional increase in cerebral

blood flow. During incidents of hypoxia, the brain is not capable of significant anaerobic

metabolism as a result of the high metabolic rate of the neurons. The more prolonged the

hypoxia, the more diffuse and extensive the regions of the brain that are affected. The most

susceptible regions are the brainstem, hippocampus and cerebral cortex. Injury continues to

progress and ultimately becomes irreversible if oxygenation is not re-established. Necrosis

mainly results from acute cell death, but delayed apoptosis may also occur following the

hypoxic episode. Even though it is essential to save the tissue, reperfusion of oxygenated

blood may also lead to cell death, primarily due to the production of reactive oxygen species

and inflammatory cell infiltration. (21, 22)

9

Cardiac muscle requires approximately 1.3 ml of oxygen per 100 g of myocardial tissue per

minute, but receives about 8 ml per minute under normal physiological conditions. If the

oxygen supply falls to critically low levels, energy metabolism changes from mitochondrial

respiration to anaerobic glycolysis. At the same time, effective myocardial contractions

decrease, the patient becomes bradycardic and eventually contractions terminate. Lactate

and protons accumulate in cardiac myocytes, leading to acidosis, increased osmotic load

and cellular oedema. Intracellular calcium rises, most likely as a result of the joint action of

the Na+/H+ and Na+/Ca2+ exchangers triggered by cellular acidosis. If sustained, this will

ultimately result in cell necrosis. (22, 23)

Restoration of oxygenated arterial flow is essential to re-establish aerobic metabolism and

save the hypoxic cardiac myocytes. Similar to neuronal tissue, the reperfusion in itself will

however lead to further injury. “Myocardial stunning” is a type of reperfusion injury, which

was defined by Braunwald and Kloner (24) as “prolonged, post ischemic dysfunction of

viable tissue salvaged by reperfusion”. Even though the myocardium is viable and aerobic, it

displays momentary contractile failure. Reactive oxygen species during reperfusion is

presumably the basis of the contractile failure. Changes in calcium homeostasis, instead of

“alteration of the contractile apparatus” are most likely the result of the production of

reactive oxygen species and the cause of the dysfunction. (22-24)

2.3 Incidence of airway complications

The incidence of the difficult airway published in the literature varies considerably. This may

be due to different definitions regarding the difficult airway, different patient populations

and varying levels of clinician experience, making it difficult to compare figures. (11)

In 1990, a closed claims study of 1541 adverse anaesthetic outcomes (mostly occurring

between 1975 and 1985) was published by the ASA. It revealed that adverse outcomes

related to respiratory events were responsible for most of the claims (34%), of which 85%

led to death or permanent brain damage. The majority of the respiratory events occurred

due to one of three mechanisms: inadequate ventilation (33%), oesophageal intubation

(18%) and difficult tracheal intubation (17%). Most adverse consequences were considered

avoidable with pulse oximetry, capnometry or both. In 76% of the claims, care was judged

to be substandard. (17)

10

In a subsequent closed claims analysis published by ASA in 2005, 179 claims for difficult

airway management from 1985 to 1999 were reviewed. Claims were divided into two time

periods, 1985-1992 and 1993-1999 (after introduction of the ASA Difficult Airway

Guidelines) to compare outcomes. Death or brain damage for claims related to induction of

anaesthesia decreased significantly from 1993-1999 compared to 1985-1992. This reduction

may be as result of better airway management by following the ASA guidelines, but may

also be due to improved safety with use of new airway devices such as SADs and awake

intubation techniques. (14)

Although the closed claims studies give us access to information about adverse events, they

have limitations that should be considered when interpreting the data. In these studies,

there was no information about the number of anaesthetics performed during this time

period. There is therefore no denominator to calculate the risk of anaesthetic injury. In

addition to that, the closed claims datasets only collect data from cases that led to litigation.

Some patients will not claim even after serious injury, while other patients will file claims

without any obvious injury. Another limitation of the closed claims studies is that the

information is collected and interpreted retrospectively. (18, 25)

A retrospective study by Connelly et al (26) in a tertiary teaching hospital in the United

States in 2006, reviewed the management of unanticipated difficult airways over a seven

year period. Over this time period, an unanticipated difficult airway occurred in 446 patients

of the 168 000 general anaesthetics performed, making the incidence 0.26%. Face mask

ventilation was only impossible in five of these patients and none of them required a

surgical airway.

In 2011, Cook et al (27) published the results of the “Fourth National Audit Project of the

Royal College of Anaesthetists and the Difficult Airway Society” (NAP4) regarding the major

complications of airway management in all of the 309 National Health Service hospitals in

the UK. It was a prospective study that included all the cases of complications of airway

management that resulted in “death, brain damage, the need for an emergency surgical

airway, unanticipated ICU admission, or prolongation of ICU stay”. A total of 133

complications related to anaesthesia occurred over the period of a year (airway

complications in the intensive care unit or emergency department was audited separately).

11

The number of anaesthetics administered over the same period was approximately 2.9

million, making the estimated incidence of difficult airway incidents one in 22 000 cases. The

authors however commented that this figure is most likely an underestimation and that

several factors may have led to under-reporting. They stated that there may have been

individual or institutional reluctance to release information due to expected litigation or

investigation. Statistical analysis indicated that the actual incidence might be four times

higher than reported by the involved hospitals. This was the largest study of its nature

performed to date.

The “Saving Mothers 2008-2010: Fifth report on the Confidential Enquiries into Maternal

Deaths in South Africa” provided statistics regarding airway complications for this country.

Of the 121 anaesthesia related maternal deaths for these three years, 16 deaths were

during general anaesthesia, of which 8 (50%) were as a direct result of failed intubation. (28)

These different studies give an indication of the incidence of complications related to airway

management, but they also show that it is challenging to obtain accurate statistics.

2.4 Difficult airway algorithms

The ASA Task Force on management of the difficult airway defined a difficult airway as “the

clinical situation in which a conventionally trained anaesthesiologist experiences difficulty

with facemask ventilation of the upper airway, difficulty with tracheal intubation, or both.

The difficult airway represents a complex interaction between patient factors, the clinical

setting, and the skills of the practitioner.” (9)

Several algorithms and guidelines for management of the difficult airway have been

formulated by national societies as well as by local institutions (2, 5, 7, 11). Developing

guidelines for the emergency management of the difficult airway poses a unique challenge.

The reason for this is that there are numerous options and the most appropriate choice

depends on the specific clinical setting. These guidelines therefore need to be simple and

easy to follow but they also need to provide enough guidance for a wide range of clinical

scenarios. (2)

12

The ASA Practice Guidelines for the Management of the Difficult Airway

The ASA published the “Practice Guidelines for the Management of the Difficult Airway”,

which was initially issued in 1993, in response to the closed claims study (6). These

guidelines have been updated twice since the original publication (9, 29). According to the

ASA, practice guidelines are “systematically developed recommendations” that assist the

physician and patient to make appropriate health care decisions (9). These

recommendations can be “adopted, modified or rejected” according to the requirements

and limitations of an institution, but they are not supposed to substitute local protocols and

their use cannot guarantee any definite result (9).

The evidence for the preparation of the ASA guidelines was obtained from two major

sources: scientific evidence from literature published in peer-reviewed journals, and

opinion-based evidence from survey findings of expert consultants and active ASA

members. The consultants and ASA members, who participated in the survey, strongly

agreed that anaesthesiologists ought to have a pre-planned strategy for intubation of the

difficult airway. This should include an approach to an awake intubation for an anticipated

difficult airway, a patient who is difficult to intubate but who can still be ventilated, and for

the emergency CICV scenario. The most recent ASA guidelines include suggestions on

evaluation of the airway, preparation for difficult airway management, strategy for the

intubation of the difficult airway, strategy for extubation of the difficult airway and follow-

up care. (9)

In these guidelines, non-invasive interventions include awake intubation techniques, video-

assisted laryngoscopy, intubating stylets or tube-exchangers, SADs, intubating laryngeal

mask airways (ILMA™), rigid laryngoscopic blades of different design and size, fibre-optic

intubation and lighted stylets or light wands. Confirmation of tracheal intubation should be

done using capnography. Regarding invasive airway access, the guidelines suggest surgical

or percutaneous airway, jet ventilation or retrograde intubation. (9)

The algorithm based on these guidelines starts with advice on airway assessment as well as

management options that should be considered before induction of anaesthesia. It then

goes through a series of steps, stating options at each stage of the management of the

difficult airway scenario. (9)

13

Critique of this algorithm is that it is complicated and allows for too many management

choices at each stage, making it difficult to recall and apply in an emergency situation. (2, 7)

Canadian Airway Focus Group recommendations

In 1998, the Canadian Airway Focus Group (CAFG) developed “strategies for the

management of the unanticipated difficult airway”, of which an update was published in

2013. The focus group involved in the update included nineteen experts with backgrounds

in anaesthesia, emergency medicine and intensive care. For the development of these

guidelines, literature searches were conducted and the quality of the evidence was

reviewed. Where the quality of the evidence was poor or lacking, “expert opinion” was

sought through consensus. (8, 11)

An algorithm for “difficult intubation encountered in an unconscious patient” was

developed based on the CAFG guidelines. This straightforward algorithm progresses through

a limited number of steps, including the “primary approach to tracheal intubation” (Plan A),

“the alternative approach to tracheal intubation” (Plan B), and an exit strategy. (11)

For the primary approach (Plan A) to succeed, it is suggested that conditions should be

optimised by adequate preparation, familiarity with airway adjuncts, proper positioning of

the patient and appropriate pharmacotherapy. If difficult direct laryngoscopy is

encountered, there is strong evidence for external laryngeal manipulation to improve the

view. The tracheal tube introducer is an effective aid when restricted view of the larynx is

encountered and the CAFG suggests its immediate availability at all airway management

locations. If mask ventilation is found to be difficult, exaggerated head extension (unless

contra-indicated), placement of correctly sized oropharyngeal and/or nasopharyngeal

airways and using a “two-handed technique” are suggested. (11)

Should the initial intubation plan (Plan A) fail after two attempts, but ventilation is still

adequate, a different device or operator (Plan B) should be employed. Various alternatives

to direct laryngoscopy have been proven to be effective, including the ILMA™, intubating

lighted stylets, several different videolaryngoscopes and fibreoptic intubation devices. The

CAFG recommend that all anaesthetists should be familiar with at least one of these

alternative techniques and that the equipment should be easily accessible. Attempts at

14

tracheal intubation must be minimised as repeated attempts increases patient morbidity.

(11)

Exit strategies in an adequately oxygenated unconscious patient includes awakening the

patient if feasible and appropriate, proceeding with surgery using a face mask or SAD,

obtaining equipment and/or more skilled help or, in rare circumstances, proceeding with

surgical airway access. (11)

If oxygenation is unsuccessful, an emergency strategy is suggested without delay. The

emergency strategy involves calling for help, one attempt at a SAD if not already attempted

and progression to a cricothyroidotomy if unsuccessful. The CAFG suggests capnography

after tracheal intubation or cricothyroidotomy to confirm correct tube or cannula

placement. (11)

The CAFG recommendations include special considerations with regards to obstetric and

paediatric airway management. (11)

Difficult Airway Society Guidelines for the management of the unanticipated difficult

airway

In 2004 the Difficult Airway Society (DAS) from the UK developed guidelines for the

management of the unanticipated difficult intubation in an adult, non-obstetric patient (7).

In response to the findings of NAP4 (27), Frerk et al (10) published an update of the DAS

guidelines in 2015, to keep up with the change in clinical practice, the development of new

pharmacological agents as well as the introduction of new equipment such as

videolaryngoscopes. These guidelines provide a sequence of plans to manage the

unanticipated difficult airway in order to assist the anaesthetist in the decision-making

process in an emergency situation. Human factors are recognised and discussed in the

guidelines, as a detailed analysis of the NAP4 study identified “human factor influences” in

all the cases of adverse airway outcomes.

Plan A consists of facemask ventilation and the initial tracheal intubation plan. Optimal

intubating conditions should be ensured by proper positioning, adequate pre-oxygenation

and appropriate choices of an induction agent and a neuro-muscular blocking agent.

Suggestions to improve difficult mask ventilation include airway manoeuvres such as “chin-

15

lift” and “jaw-thrust”, as well as oro- and nasopharyngeal airways. The guidelines suggest

that all anaesthetists should be trained in using a videolaryngoscope and that it should be

readily available. During laryngoscopy, external laryngeal manipulation should be applied if

the laryngeal view is poor and the use of a gum-elastic bougie (GEM) should be considered.

The DAS agrees that attempts at laryngoscopy should be limited to three, as multiple

attempts carries significant morbidity for the patient and can lead to a CICV situation due to

airway trauma. Tracheal intubation should be confirmed with capnography. (10)

If Plan A has failed, Plan B should be employed, which consists of maintaining oxygenation

by inserting a SAD, preferably a second generation SAD. If the insertion of the SAD was

successful and ventilation has been confirmed with capnograhy, the anaesthetic team

should stop and consider the following options: allow the patient to wake up, intubate the

trachea through the SAD with a fibre-optic scope, proceed with the surgery or in rare

circumstances, proceed to a surgical airway. If Plan B fails after three attempts (with

different types or sizes of SADs), Plan C should be implemented. (10)

Plan C involves a final attempt at face-mask ventilation. If it is possible to oxygenate the

patient with face-mask ventilation, the neuro-muscular blockade should be reversed and

the patient should be woken up. If face-mask ventilation is impossible, it is advised to fully

paralyse the patient again to optimise intubating conditions and one last attempt should be

made at rescuing the airway with a non-surgical technique. Re-paralysing the patient is a

new recommendation and this suggestion is different from all of the other guidelines. If it

fails, Plan D should be implemented without delay. (10)

Plan D involves obtaining emergency “front-of-neck” access. The scalpel cricothyroidotomy

has been shown to be the quickest and most reliable technique of securing the airway in a

CICV situation and it is the technique that is advised in these guidelines. (10)

These guidelines end with post-operative care and follow-up of the patient. The

anaesthetist should inform the patient about the airway difficulties experienced and an

“airway management plan” should be documented. (10)

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The Vortex approach

In 2008, Nicholas Chrimes, an Australian anaesthesiologist, in conjunction with medical and

nursing staff experienced in anaesthetics, emergency medicine or intensive care, devised

the Vortex approach. This approach serves as a straightforward “cognitive aid”, to

encourage a structured approach rather than “progression through a linear algorithm”,

when dealing with a difficult airway. (2)

The Vortex model emphasises that alveolar oxygen delivery is the most important goal of

airway management, even if it is achieved with a different method than what was initially

planned. The secondary goals such as carbon dioxide elimination and airway protection may

have to be compromised. Repeated attempts at trying to establish a definitive airway with

excessive airway manipulation may turn a situation where oxygen delivery was possible,

into a CICV situation due to airway trauma and oedema. (2)

The three frequently used non-surgical techniques to ensure ventilation and oxygen delivery

are a face-mask, a SAD and an endotracheal tube. In case of the unanticipated difficult

airway, success at establishing delivery of oxygen will be most likely with techniques that

the anaesthetist is most comfortable with. The Vortex approach suggests only three

attempts at each of the non-surgical methods. If optimal attempts have been made and

there is no sign of recovery and spontaneous ventilation, progression to a surgical airway is

indicated, irrespective of the patient’s oxygen saturation. The surgical methods can be

classified into the emergency surgical airway and the definitive surgical airway. (2)

The Vortex model metaphorically describes airway management as a funnel (Figure 2.1).

The horizontal surface at the top of the funnel is termed the “Green Zone”, which describes

the situation where alveolar oxygenation is maintained and there is time to consider

alternative management options before commencing with any further airway

manipulations. (2)

17

Figure 2.1 The airway management funnel of the Vortex model

The funnel component symbolises any situation where airway patency is not ensured and

“optimal attempts” at the three non-surgical airway techniques should be made in any

order appropriate to the clinical situation, as seen on the overhead view of the funnel in

Figure 2.2. The narrowing of the funnel emphasises the fact that time and options are

diminishing and eventually spirals down to where all non-surgical techniques are exhausted.

In this case, the anaesthetist should progress to a surgical airway without delay.

Figure 2.2 The overhead view of the funnel of the Vortex model

18

The Vortex approach encourages five “optimisation strategies” that should be employed in

the emergency situation of a difficult airway, including:

manipulation manoeuvres of the head and neck and applying external laryngeal

pressure;

using airway adjuncts, such as oropharyngeal airways, introducers, bougies and

stylets;

changing the size and type of equipment;

suctioning the airway to remove blood and secretions; and

optimising pharyngeal muscle tone, either by giving a muscle relaxant to optimise

intubating circumstances or by allowing the patient to wake up and maintain his/her

own airway. (2)

SASA Airway Management Recommendations

In 2008, SASA published recommendations for South African hospitals and clinics on

suggested airway management resources in operating theatres. These guidelines include

suggestions on airway assessment as well as the necessary routine and emergency airway

equipment required in the different settings. They included both the 2004 DAS and 2003

ASA difficult airway algorithms and suggestions on difficult airway management. An update

of these guidelines was published in 2014. This update includes new airway equipment that

was introduced since the previous guidelines were published as well as the 2013 ASA

difficult airway algorithm, the 2012 DAS guidelines for extubation of a difficult airway and

the Vortex approach. (12)

2.5 Airway management equipment

In 2013 Paolini et al (30) published a review article in which they stated: “Thirty years ago,

anaesthesiologists had to rely solely on bag-and-mask ventilation, and/or direct

laryngoscopy (DL) with tracheal intubation to oxygenate the patient. Several alternative

tools are now available including a variety of supraglottic devices, intubating laryngeal mask

airways, gum elastic bougies or stylets, fibreotic bronchoscopes, modifications of blades,

and videolaryngoscopes (VL’s)”. In this section, these and other airway devices will be briefly

discussed.

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Oropharyngeal and nasopharyngeal airways

To maintain a patent airway in an anaesthetised patient, simple manoeuvres like the jaw-

thrust and/or extension of the atlanto-occipital joint are often sufficient. If these techniques

are ineffective, the pharyngeal obstruction must be alleviated and the easiest way to ensure

this is by inserting an oropharyngeal or nasopharyngeal airway. (31)

The oropharyngeal airway is designed to open the pharynx by separating the tongue and

epiglottis from the posterior pharyngeal wall thereby creating an artificial airway. The most

widely used oropharyngeal airway is the Guedel airway. The Guedel airway is available in a

selection of sizes. These devices may function as a bite block in an intubated patient, but

dental damage may occur. In a patient whose pharyngeal reflexes are still present, inserting

an oral airway may lead to gagging, retching or laryngospasm. (31)

The nasopharyngeal airway should be inserted through the nares and passed along the floor

of the nasal passage to beyond the soft palate to allow the tip to lie in the oropharynx,

above the epiglottis. To prevent loss of the tube into the nose and limit depth of insertion, it

has a flange or “lip” at the proximal end. The right size can be measured from the tip of nose

to the trachus of the ear. Nasopharyngeal airways are better tolerated than oropharyngeal

airways during light anaesthesia. Insertion may be complicated by epistaxis and their use

should be avoided in patients with a known coagulopathy. (31)

Bougies and stylets

If the larynx cannot be visualised during laryngoscopy, or only the epiglottis is visible,

intubation can be achieved by either manipulating the curvature of the endo-tracheal tube

with a plastic-coated pliable metal stylet or by passing a “gum-elastic bougie”(GEM) into the

trachea and rail-roading the tracheal tube over it (31). The GEM was designed in the 1970’s

by Dr. P Venn as the “Eschmann Tracheal Tube Introducer” (32). A study done by Gataure et

al (33), compared the efficacy of the stylet and the GEM in a 100 simulated difficult

intubations. The GEM was successfully placed in the trachea after two attempts in 96% of

patients, while the intubations with the intubating stylet were only successful after two

attempts in 66% of cases. These authors recommended that the GEM should be easily

accessible and used in preference to a stylet when the view of the larynx is poor.

20

Kidd et al (34) evaluated the two signs that are used in confirming tracheal placement,

namely “clicks” that are produced when the tip of the bougie slides over the tracheal

cartilages and “hold-up” when the bougie is advanced and the tip reaches the smaller

bronchi. Out of 98 cases, “clicks” were documented in 88 cases and “holp-up” occurred at

20 to 40 cm in all cases of correct tracheal placement.

The GEM has been shown to be extremely effective due to its angled tip and the “memory”

of the material to keep the curvature (31). In a study done by Latto et al (35) in 2002, 199

out of 200 difficult airways were successfully intubated with the GEM, of which 89% of first

attempts were successful. Nolan and Wilson (36) evaluated the routine use of the GEM to

aid intubation, versus conventional intubation. In cases where only the epiglottis was visible,

the use of a GEM was only ten seconds longer than conventional intubation and the bougie

was used in three cases where conventional intubation failed. The incidence of a sore throat

and hoarseness between the two groups was not significantly different.

Light wand and Trachlight™

The lighted stylet or light wand developed from the intubating stylet to allow for trans-

illumination of the trachea as an aid to position the tracheal tube correctly. The original

devices are now essentially outdated, as they have been replaced by newer improved

developments such as the Trachlight™ and optical stylets. The Trachlight™ is a form of blind

intubation and was designed to enable intubation without laryngoscopy. In a clinical trial by

Hung et al (37), 950 elective surgical patients were divided into two groups, either to be

intubated via direct laryngoscopy or using the Trachlight™. The time to intubation was

similar in both groups but the Trachlight™ group had a significantly lower incidence of

airway trauma (10 versus 37 patients) and sore throat post-operatively. Success rates of

intubation were similar in both groups, but the ease of intubation with the Trachlight™, in

contrast to laryngoscopy, did not appear to be affected by the anatomical variations of the

upper airway. (31, 37)

Supra-glottic airway devices

The SAD has transformed airway management as it provides a very effective alternative to

endo-tracheal intubation and face mask ventilation. It has also been proven to be an

excellent rescue device when faced with a difficult intubation or CICV scenario and it is

21

recommended in all the difficult airway algorithms for this purpose. In a study by Parmet et

al (38), the SAD was successful in 94% (16 out of 17) of cases for rescue ventilation in a CICV

scenario. (39)

Some common features of SADs are:

an inflatable cuff (bowl) that is placed above the level of the larynx;

laryngeal visualisation is not needed for insertion (can be inserted blindly);

soft distal tip that lodges in the proximal oesophagus behind the cricoid cartilage;

tracheal isolation from gastric contents cannot be ensured if reflux or vomiting

occur;

large bore airway tube can serve as a conduit for other devices such as endo-tracheal

tubes or fibreoptic scopes; and

standard 15 mm connector. (31)

The original SAD was the classic laryngeal mask airway (cLMA™), which came into use in

1988. This device has been extensively studied and its use is widely advocated in the

literature. It is used in approximately 50% in anaesthetics in the UK. Limitations of the

cLMA™ are however that is does not protect against aspiration and does not allow for

ventilating pressures of more than 20 cmH2O. The higher incidence of obesity in the surgical

population (and therefore higher incidence of gastro-esophageal reflux), the rise in

laparoscopic procedures, as well as the fact that more procedures are being done in the

lithotomy position, have limited its use in certain settings. (40)

The ILMA™ or Fastrach™ was designed to aid tracheal intubation, usually using a blind

technique, but can also be assisted with a fibreoptic scope. The ILMA™ was manufactured

by the same company as the original cLMA™, but has a significantly different design. It has a

shorter, wider airway tube with a 110⁰ angle, constructed of stainless steel covered with

silicone. The device comes with a soft silicone tracheal tube that is specifically designed to

easily pass through the curve of the airway tube. (31)

When the ILMA™ became available in 1997, Kapila et al (41) did a preliminary assessment

of the device in 100 patients. Intubation was successful in 93 patients, and seven of the

failures occurred during the first 20 intubations. This demonstrated that there is a learning

22

curve associated with the use of the ILMA™. Baskett et al (42) followed with a multicentre

trial in 1998 where the ILMA™ was used in 500 patients by 17 different anaesthetists. The

success rate of blind intubation was 96.2 % (481 cases). Of the 19 failed intubations, 17

occurred within the anaesthetist’s first 20 attempts, confirming the learning curve

suggested by Kapila. The authors recommended that the ILMA™ should form part of the

difficult airway equipment in theatres and emergency departments. In a review by Caponas

(43) of nine studies that evaluated the ability of the ILMA™ to facilitate blind intubation, the

success rate of intubation was 95.7% in 1110 patients included in the various trials.

The Laryngeal Tube (LT™) was first manufactured in 1999 and the initial design has since

then been modified several times. It consists of airway tube with a distal cuff (designed to

lie in the oesophageal inlet) and a larger proximal cuff (to lie in the oropharynx). Ventilation

occurs through openings between the two cuffs. A study by Ocker et al (44) in 2002,

compared the LT™ with the LMA™ in 50 patients undergoing general anaesthesia.

Ventilation and oxygenation of the two devices compared well, and the LT™ allowed for

slightly higher ventilation pressures. Cook et al (45) followed with a similar study in 2003 in

72 patients, that also showed that there were no significant differences in the adequacy of

ventilation and that both devices had a similar incidence of post-operative complications. A

major drawback of the LT™ is that there is a high frequency of partial or complete airway

obstruction (2-40%) because of its small ventilation orifices and the fact that the tube-like

shape allows for axial rotation in the airway. (31, 45, 46)

Cook (40) classifies SADs into first generation and second generation devices. The first

generation devices include the simple airway tubes discussed above, while the second

generation devices are those designed with the ideal of decreasing the risk of aspiration of

gastric contents. These include the LMA™ Pro-Seal (PLMA™), the supreme LMA™ (SLMA™),

the i-gel™, the laryngeal tube suction (LTS™) and the Combitube™.

The PLMA™ was introduced in 2000 and is a valuable addition to airway management. It’s

design provides a better seal during controlled ventilation and it has a port for the passage

of a gastric drainage tube (31, 47). A review article by Cook et al (47) revealed that first time

success with insertion of the PLMA™ is 8% lower than the cLMA™ (85% versus 93%). If a

bougie-guided technique is however used to insert the PLMA™ (by placing a bougie into the

23

oesophagus with the aid of a laryngoscope and rail-roading the PLMA™ over it) the success

rate is almost 100%. This review also found that the PLMA™ has a 50% better airway seal

that the cLMA™ and it has been used successfully in laparoscopic and abdominal surgery as

well as in obese patients. The PLMA™ has been effective in airway rescue situations and

might be the most logical choice for failed intubation after a rapid sequence induction (31,

48).

The supreme LMA™ (SLMA™) was introduced in 2009 (31). It is a single use device with

design features of both the ILMA™ (fixed curved airway tube for easy insertion) and the

PLMA™ (port for gastric access, bite block and high seal cuff to prevent aspiration) (49). A

pilot study by Van Zundert and Brimacombe (50) in 22 patients showed that successful

insertion at first attempt was obtained in all patients as well as insertion of a gastric tube

through the port. The average seal pressure was 37 cmH2O, which is significantly higher

than the cLMA™. Several studies done comparing the SLMA™ to the Pro-Seal™, found that

ease of insertion and success of gastric tube insertion were similar and that the seal

pressure was either similar or higher in the PLMA™ (49, 51, 52). The SLMA™ has been

successfully used in the prone position. In a study by López et al (53), 40 patients were

positioned prone and the SLMA™ was inserted after induction with propofol. All patients

could be adequately ventilated and a gastric tube was successfully passed in all of them. The

incidence of blood staining of the device and a sore throat post-operatively was 7.5% for

both. In another study by Sharma et al (54), 205 patients for elective spine surgery were

effectively ventilated with a SLMA™ and no cases of aspiration were recorded. The SLMA™

has also been described as an effective rescue airway even in a case where the patient was

at very high risk of aspiration of gastric content (55).

The i-gel™ is a cuffless SAD made of “medical grade” elastomer gel. It has a short wide

airway tube, an “anatomically” shaped bowl that does not need to be inflated, an elliptically

shaped stem, an internal bite block and a tube permitting drainage of gastric content (31). In

a study by Gatward et al (56) in 100 elective patients, first attempt insertion were successful

in 86 patients. The median leak pressure obtained was 24 cm H2O and one episode of

regurgitation (but not aspiration) occurred. A study comparing the use of the SLMA™ to the

i-gel™ by airway novices was done in 80 patients undergoing breast surgery by Razazzi et al

(57). First time insertion success was significantly higher (77% to 54%) with the SLMA™ than

24

the i-gel™ and a higher seal pressure and more effective ventilation was found with the

SLMA™.

A modification of the LT™ was introduced in 2002, namely the Laryngeal Tube Suction

(LTS™), of which an upgraded version, the LTS II™ was introduced in 2005. The LTS II™ has

similar pharyngeal seal than the PLMA™ and appears to be an improvement of its

predecessor (31). Evidence regarding the ease of insertion and the frequency of airway

obstruction is still lacking and more studies should be conducted to compare it with the

other second generation SADs (58).

The Combitube™ is theoretically different to other SADs as it is designed to provide effective

ventilation after being blindly placed in either the oesophagus or trachea. Similar to the

LT™, it has two cuffs. After blind insertion, the large proximal cuff is inflated to secure

placement, and then the distal smaller cuff is inflated. Ventilation is first attempted through

the first lumen that opens between the two cuffs. If this is successful, it means that the

distal cuff is in the oesophagus. If the first lumen does not provide ventilation, the second

lumen is tried, which if successful, will mean that the distal cuff entered the trachea. If the

distal end is in the esophagus, the second lumen can be used to insert a gastric drainage

tube. Complications with the use of the Combitube™ occur more frequently than in other

SADs and oesophageal rupture have been reported. The Combitube™ may still play a role in

the pre-hospital emergency setting, but not in routine anaeasthesia. Due to its cost, possible

confusion with the different lumens and trauma associated with insertion, it has largely

been replaced by other SADs. (31, 59)

SADs are complex because of the vast availability of devices and variants of each. For many

of the newer generic devices not discussed here, there is not enough research to advocate

their use and the ones that have been researched shows very little if any advantage over the

cLMA™. Regarding second generation SADs, such as the SLMA™ and the PLMA™, evidence

shows benefits and potential increase in safety compared to the cLMA™. (31)

Direct laryngoscopes

Laryngoscopes are instruments designed to obtain a view of the larynx and facilitate

tracheal intubation. The two broad categories include “direct line of sight devices” such as

the popular Macintosh laryngoscope and “indirect line of sight devices” which are optical

25

laryngoscopes with either a fibreoptic bundle, sequence of lenses or prisms, or small

cameras to convey the image to the user. This allows the user to “see around corners”, in

other words the line of sight doesn’t need to be direct. In this category, videolaryngoscopes

are becoming increasingly popular. Laryngoscopes can also be divided into rigid

laryngoscopes and flexible scopes. (31)

Intubation through visualisation of the larynx was popularised by Sir Robert Macintosh and

Sir Ivan Magill in the 1940s. The Macintosh laryngoscope blade is slightly curved and the tip

was designed for insertion anterior to the base of the epiglottis in adults. A variety of other

laryngoscope blades are also available, including several blades with a straighter design than

that of the Macintosh (for example the Miller and Seward designs). The Polio laryngoscope

blade has the same curved design as the Macintosh, but the angle between the handle and

the blade is increased from 90⁰ to 135⁰, enabling easier insertion of the blade in patients

with difficult anatomy such as restricted neck extension and large breasts. The McCoy blade

has a hinge at the tip that can be controlled by a lever on the handle. By flexing the tip,

further elevation of the vallecula and epiglottis can be obtained. It has been shown however

that it does not improve a grade four laryngoscopic view (in other words if the epiglottis

cannot be visualised). (31, 60, 61)

Rigid optical laryngoscopes

Apart from the fact that rigid optical laryngoscopes removes the need for a “direct line of

sight” they also offer the potential advantages that they have the ability to obtain a view of

the larynx with limited mouth opening and the operator does not need to apply the same

amount of force than with direct laryngoscopy. This leads to decreased cardiovascular

stimulation and enable their use in awake patients (with topical anaesthesia of the airway

only).

Rigid optical laryngoscopes can be divided into three groups based on their design, namely:

in the form of a optical or videostylet, with the device inserted into the endotracheal

tube as a guide;

a device with an incorporated channel that acts as a conduit for the endotracheal

tube; and

26

bladed laryngoscopes (or videolaryngoscopes) without a channel, that requires an

independent stylet to guide endo-tracheal tube insertion. (31, 62)

Optical stylets consist of either a pre-formed rigid or pliable metal introducer enclosing an

optical system (usually a fibreoptic system). The optical system allows the image from the

tip of the stylet to be viewed at the distal end either directly or displayed on a camera

screen. A tracheal tube is pre-loaded onto the stylet and advanced over it through the vocal

cords. To avoid trauma to the trachea, it is suggested that the stylet itself should not be

advanced into the trachea. Examples of the optical of videostylets include Bonfils™

intubating fibrescope, the Shikani Optical Stylet™, the Levitan FPS™ and the SensaScope™.

In a study done by Bein et al (63), the Bonfils™ intubating fibrescope was used as the first

choice for airway rescue in patients presenting for cardiac surgery. Intubation via

conventional direct laryngscopy failed in 25 out of 1430 patients during the study period.

Using the Bonfils™, 22 out of the 25 patients were successfully intubated on the first

attempt and two more on the second attempt. Most other optical stylets lack formal

assessment and have not been studied extensively. (31)

Rigid optical laryngoscopes with a channel to house the tracheal tube and act as a conduit,

include the Pentax Airwayscope (Pentax AWS™), the Airtraq™ and the LMA CTrach™. A

limitation of the conduit laryngoscopes is that the channel contributes to the bulkiness of

the device and therefore require larger mouth opening. Another drawback is that the use of

tracheal tubes of different sizes and design will change the “angle of exit” of the tube and

may have a negative impact on intubation success. The Pentax AWS™ consists of a flexible

stem, with a disposable plastic mount that integrates a channel for the tracheal tube as well

as one for a suction catheter. The image is displayed on a “liquid crystal display” (LCD)

screen. The Airtraq™ is a single-use, disposable device that uses a sequence of prisms and

mirrors to present an illuminated image into a “viewfinder”. The LMA CTrach™ is a modified

version of the ILMA™ that consists of an ILMA™ containing fibre-optic bundles to display an

image onto a screen. According to a systematic review by Healy et al (62) in 2012, all three

of these devices have demonstrated a high overall success rate in cases of predicted difficult

airways as well as for use as a rescue device after failed direct laryngoscopy. (31)

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Bladed optical laryngoscopes include the Bullard™ laryngoscope, the McGrath Series 5™, the

GlideScope™ and the C-Mac™. The Bullard™ laryngoscope was the “standard” choice in this

group for years, but has now largely been replaced by newer developments. It was designed

to be used for patients with limited mouth opening and neck extension and uses fibreoptic

technology to display and image into an eyepiece. The McGrath™ is a videolaryngoscope

with a detachable metal curved “CameraStick” that is covered with a disposable clear plastic

laryngoscope blade. It has been shown to be useful in difficult intubations but no large scale

comparative studies have been done. The C-Mac™ consists of metal reusable laryngoscope

blade encasing a camera and a light emitting diode at its tip, transmitting the image onto a

screen. The GlideScope™ consists of a curved plastic blade with the same shape as the

Macintosh blade. It has a camera on the tip that transmits the image to a screen. In a

retrospective review Aziz et al found that the Glidescope™ was successful in 98% of cases

where it was used as the primary method of intubation, and in 94% of cases where it was

used as rescue technique after unsuccessful direct laryngoscopy. They found that previous

neck surgery, radiation or a neck mass were the strongest predictors of unsuccessful

intubations with the Glidescope™. Both the C-Mac™ (and its predecessor the V-Mac™) and

the Glidescope™ have been extensively studied and reviews done by Healy et al (62) as well

as Paolini et al (30) demonstrated a high success rate with strong evidence supporting their

use. A potential drawback of these devices is the fact that even if easy visualisation of the

vocal cords is obtained, inserting the tracheal tube may be difficult or problematic. Most of

these devices therefore need to be used with a pre-curved intubating stylet introduced into

the tracheal tube. Aziz et al (64) stated that anaesthetic providers “should maintain their

competency with alternate methods of intubation, especially for patients with neck

pathology.” (31)

Flexible fibreoptic scopes

The technique of fibreoptic intubation has become the “gold-standard” for awake

intubation in cases where a difficult airway is expected and should be mastered by every

anaesthetist. The advantages of the fibreoptic scope are its flexibility and ability to “see

around corners”. It can be placed through SADs, it can be used in awake patients, it can be

placed further into the bronchial tree than any other device and it can be inserted nasally. It

is not the answer to every airway problem but occasionally the only practical solution. It is

28

however a very expensive device that is easily damaged and requires a lot of practice and

skill to be used effectively. This limits its use in emergency airway management in certain

settings. The three leading manufacturers of flexible fibreoptic scopes in South Africa are

Karl Storz, Pentax and Olympus. (31, 65)

Retrograde intubation

Retrograde intubation involves inserting a guidewire through the larynx, through the

cricothyroid membrane in a cephalad direction and using this as a guide to railroad a

tracheal tube from above. Several techniques have been described and different retro-grade

intubation sets are manufactured commercially. It is typically done in an awake patient with

an anticipated difficult airway, but it has a place in the unanticipated difficult airway as well.

Advantages of this technique is that it can be used when there are blood or secretions in the

upper airway, as a direct glottic view is not required to perform this technique. It is less

invasive than performing a needle or surgical cricothyroidotomy, but should be avoided

when a patient has a bleeding disorder or when there is infection or tumour over the access

site. Complications of this technique include bleeding or haematoma formation, surgical

emphysema and infection. (31, 66)

2.6 Cricothyroidotomy

Methods and devices for performing a cricothyroidotomy

A cricothyroidotomy is not a permanent solution, but it is an urgently indicated, life-saving

procedure when a patent airway cannot be established by non-surgical means (67). It can be

accomplished by a surgical incision or by puncturing the cricothyroid membrane. Puncturing

can be done with a narrow-bore (internal diameter of ≤2mm) kink-resistant needle, a wide-

bore (internal diameter of ≥ 4mm) “cannula-over-trocar” or wire-guided (Seldinger)

technique, with dilatation (13). The use of 14-16 gauge intra-venous cannulae is commonly

described, but these cannulae are not kink-resistant and their use for this purpose should be

avoided (68).

In a study by Craven and Vanner (69), a lung model was created and used to determine the

efficiency of different modes of available cricothyroidotomy devices. They showed that after

insertion of a narrow-bore cannula (the 13 gauge commercially available Ravussin cannula),

29

a high-pressure oxygen source is required to adequately ventilate the lungs (69). However,

for adequate expiration to occur, the upper airway needs to be patent. With increasing

upper airway resistance, the end-expiratory pressure increases due to air-trapping, and

eventually leads to the inability to ventilate, barotrauma and haemodynamic instability (13,

69). Partial or complete upper airway obstruction frequently accompanies a CICV situation,

due to laryngospasm, airway oedema (possibly as a result of multiple intubation attempts)

or distorted anatomy. A neuromuscular blocking agent might help relieve laryngospasm and

should be considered during high-pressure ventilation. If there is no high-pressure

ventilation system or kink-resistant cannula available, or the operator is not comfortable

with high pressure ventilation, it is advisable to rather perform another technique. (13)

Insertion of a wide-bore cannula (>4 mm internal diameter) has the advantage of providing

better minute volumes and better conditions for expiration (69, 70). This can be explained

by using Poiseuille’s law, which states that “flow is proportional to the fourth power of the

radius” (71). A conventional breathing system can be used with these devices. If the device

is uncuffed, significant air-leaks through the upper airway can however lead to lower tidal

volumes (69, 70). Craven and Vanner (69) suggested that by artificially increasing upper

airway resistance, alveolar ventilation could be improved, but Sulaiman et al (70) disagree,

stating that this technique “has not been formally studied and requires an additional,

potentially unreliable, manoeuvre in a crisis situation.” Hamaekers and Henderson (13)

agree that the use of uncuffed tubes should be avoided in the emergency situation and that

only methods that provide reliable re-oxygenation ought to be employed.

Several different cricothyroidotomy sets have been developed and are available

commercially (71). The wide choice makes it difficult to know what device is most

appropriate to use in an emergency (71). The Quicktrack II® (manufactured by VBM) and the

Portex® cricothyroidotomy kit (PCK®) are examples of cuffed, needle-over-trocar devices. A

study done by Murphy et al (72) in a porcine model, favoured the Quictrack II® above the

PCK®, due to the higher success rate of insertion and lower complication rate. The insertion

of the PCK® was associated with a high incidence of posterior tracheal wall injury and

creation of false tracts.

30

Wire-guided cricothyroidotomy airways use the Seldinger technique for insertion, a

technique familiar to most anaesthetists (68). The Cook Melker® is an example of a

commercially available wire-guided cricothyroidotomy device and a variety of cuffed and

uncuffed sizes are available (13, 68). Sulaiman et al (70) found that the ease and success

rate of insertion of a cuffed Melker® compared well with a larger uncuffed device. The

cuffed device was significantly more effective in attaining adequate ventilation. Murphy et

al (72) found that the insertion time for the Melker® was significantly longer than the

Quicktrack II® and the surgical approach, but participants rated the Melker® significantly

easier to use than all other devices tested in this study.

In summary, the ideal characteristics of an emergency cricothyroidotomy device include:

internal diameter of ≥ 4 mm in order to provide an adequate canal for both

oxygenation and ventilation;

cuffed devices, to provide protection against aspiration and prevent air leakage;

ability to connect to 15 mm standard anaesthetic circuit;

features that minimises collateral damage;

intuitive and easy to use designs;

long shelf life;

durability; and

kink resistant cannulae. (67, 73)

Based on the findings in the NAP4 (27) study, the latest DAS guidelines suggest the surgical

cricothyroidotomy as the “fastest and most reliable method of securing the airway” in a

CICV situation (10). A meta-analysis by Hubble et al (74) of the success rate of alternative

airway devices and cricothyroidotomy techniques when managing a difficult airway or CICV

scenario in the pre-hospital setting, showed a success rate of 65.8% for the needle

cricothyroidotomy vs 90.5% for the surgical cricothyroidotomy. In the closed claims analysis

published by the ASA in 2005 (14), disastrous implications of the failed needle

cricothyroidotomy were reported, as well as incidences of successful surgical technique

after the failure of a needle or cannula cricothyroidotomy. The authors stated that “for a

surgical airway to be successful as a rescue option, it must be instituted early in the

management of the difficult airway.”

31

There are several techniques to perform a surgical cricothyroidotomy, and no technique has

been shown to be superior, but according to the DAS guidelines the common steps include:

“neck extension, identification of the cricothyroid membrane, incision through the skin and

cricothyroid membrane, and insertion of a cuffed tracheal tube.” Complete neuromuscular

blockade is also suggested, while using a SAD, mask or nasal insufflation to administer 100%

oxygen. (10)

Anatomy relevant to the performance of a cricothyroidotomy

Figure 2.3 Anterior midline structures in the neck

The anterior midline structures in the neck from superior to inferior are the mandible, floor

of the mouth, hyoid bone, thyrohyoid membrane, thyroid cartilage, cricothyroid membrane

and cricoid cartilage, as depicted in Figure 2.3. The cricothyroid membrane consists of thick

fibro-elastic tissue. The cricoid cartilage is situated at the level of the sixth cervical vertebra

and is the only complete cartilaginous ring in the larynx and trachea. It functions as a stent

to keep the airway patent and protects the esophagus from injury during a

cricothyroidotomy. The true vocal cords are approximately 10 mm above the cricothyroid

space. No major arteries, veins or nerves are present in the region of the cricothyroid

membrane. Superficial veins might be present in the pre-tracheal and superficial cervical

fascia. Therefore, venous haemorrhage may occur even when a midline cricothyroidotomy

is performed. In some people, part of the thyroid gland may extend to the level of the hyoid

bone and can be injured during a cricothyroidotomy. (68, 75)

In children, the thyroid cartilage is difficult to palpate as it only develops in during

adolescence. The cricothyroid membrane is situated more cephalad and is shorter than in

adults (3 mm compared to 10 mm). The cricoid cartilage is the narrowest segment of the

infant airway, and has a higher chance of being damaged during a cricothyroidotomy. It is

32

easier to inadvertently penetrate the posterior tracheal wall because of the narrow, more

flexible airway. Children are more prone to subglottic stenosis because of the more fragile,

looser, softer mucosa. For these reasons, only a needle cricothyroidotomy or a formal

tracheostomy should be performed in children younger than 12 years of age. (75)

2.7 Implementation of and adherence to algorithms – what

prevents us?

Despite the availability of prescribed guidelines and algorithms, as well as a wide array of

airway equipment, it has been shown that anaesthetists do not use these resources

appropriately when faced with an airway emergency (4, 76, 77).

A simulation study in a large teaching hospital in Glasgow, UK in 2009 assessed the

readiness of anaesthetists and anaesthetic assistants to manage the CICV scenario. Ninety-

seven anaesthetists with different levels of experience and 63 assistants were included in

the study. The participants’ knowledge of the location of the difficult airway trolley was

tested, which showed that 62.9% of anaesthetists could not locate either of the two difficult

airway trolleys in the theatre complex. A CICV scenario was simulated and success was

regarded as being able to insufflate a dummy lung. Several different devices were available

to perform a cricothyroidotomy, but were only given to the anaesthetist if specifically

requested. Only 37.1% of anaesthetists chose a surgical airway technique in keeping with

the (then most recent) DAS guidelines, which was either a surgical airway or a percutaneous

technique with a kink-resistant cannula. Of the 36 anaesthetists who chose jet ventilation,

15 could not find the correct oxygen supply outlet. Even though this study only included

anaesthetists from one hospital, it emphasised the fact that anaesthetists are not well

prepared for CICV scenarios and do not apply guidelines in clinical practice when in high-

pressure situations. (4)

Two Danish studies done in 2001 and 2004 respectively, showed that there is definite room

for improvement in airway training of anaesthesiologists. Kristensen and Møller (76) did a

survey among all the members of the Danish Society of Anaesthesiologists asking about

their “experience, behaviour and availability of various items of equipment”. Of the 436

respondents, approximately two thirds had access to a fibre-optic scope, but 67% had little

33

or no experience in performing awake intubations for patients with suspected difficult

airways, as is suggested by the ASA algorithm. Furthermore, 46% of junior registrars, 25% of

senior registrars and 18% of specialists replied that they were not exactly certain how to

oxygenate through the cricothyroid membrane. Only 54% to 71% of anaesthetists always

had a SAD available as a rescue device. Rosenstock et al (77) did a smaller single-blinded

study among 36 Danish anaesthesiology registrars that consisted of a written test on the

theory of difficult airway management. The registrars then had to attempt management of a

CICV scenario on a simulator that was able to mimic different difficult airway scenarios. Only

17% of registrars passed the written test and 97% stated that they could not recall the ASA

algorithm for the management of a difficult airway. Even though 78% had a fibre-optic

scope available, only 14% would consider using it for awake intubation in an anticipated

difficult airway. In the simulation scenario, only a small percentage of registrars made sure

that the basic difficult airway equipment was available before proceeding. Most of the

registrars were able to establish ventilation by inserting an LMA™, but did not follow the

accepted algorithms correctly. Fourteen percent immediately performed a

cricothyroidotomy without trying optimisation techniques. These studies showed that there

is a lack of knowledge and practical skills in anaesthetists when managing difficult airway

scenarios.

Greenland et al (78) looked at the reasons for the reluctance in performing an emergency

surgical airway in life-threatening airway emergencies. They identified three factors that can

be addressed in improving the outcome of such cases, namely equipment, patient factors

and the operator (or anaesthetist). Airway equipment and difficult airway trolleys should be

standardised and personnel should be familiar with the different available devices.

Greenland et al (78) highlighted the fact that following the introduction of supra-glottic

devices, the CICV situation occurs even less frequently than before and therefore

anaesthetists are becoming less familiar with the management thereof. Patient factors also

influence the decision of when to perform a surgical airway. In a patient with distorted facial

anatomy due to trauma, the decision will likely be made earlier than in a patient with less

obvious distorted anatomy (for example an undiagnosed pharyngeal mass). To improve on

this decision-making process, they suggested that training should be done in a variety of

CICV scenarios, with mannequins and animal models. The training should be “frequent,

34

recent and relevant”. They also suggest that anaesthetists should assist surgeons in

performing elective tracheostomies. The most important barrier identified however, is the

operator himself. Human factors that hamper decision-making in the emergency situation

include anxiety, fixation errors and hazardous attitudes. Greenland et al (78) identified

attitude problems from the aviation industry that may negatively affect decision making in

crisis situations. They include attitudes of “anti-authority”, impulsiveness, invulnerability, a

“macho” or competitive attitude and an attitude of resignation. Attitudes can also be

adversely affected by external pressures such as fatigue. To eliminate these human factors,

they suggest that regular mortality and morbidity discussions or “debriefing” sessions

should be held and that opportunities should be created to teach “situational awareness”.

An organisational change that can be made is improving communication between the

different specialties to include the surgeon timeously in the surgical airway if appropriate.

(78)

2.8 Formal airway training

The benefit of formal airway training is evident and therefore an increasing number of

registrar training programs have implemented formal airway rotations as part of their

curriculum.

In 2008, Smith and Koutantos (79) published a prospective audit to document the

experience that registrars were obtaining with regards to airway management. They found

that there seemed to be a decrease in the number of cases that were managed by

registrars, which might be accounted for by the decreasing allowable working hours, as well

as involvement of registrars in other duties including pain rounds, ward consultations, pre-

operative assessment clinics, epidural services and study leave. They suggested that larger

studies should be done to determine the number of cases necessary for adequate training.

They also suggested that a formal airway teaching program should be instituted with

prescribed minimum core skills and regular reinforcement thereof, and that the appropriate

equipment should be readily available.

Koppel and Reed (80) performed a survey in 1995 to determine whether trainee

anaesthesiologists are receiving formal airway management training with the various

devices and techniques. They found that only 27% of the 143 American anaesthesiology

35

training programs have specific airway rotations as part of their training program, and most

of these rotations were of short duration (one and a half weeks or less).

In 2003, Hagberg et al (81) found that 33% of American anaesthesiology training programs

have a designated airway rotation, of which 61% were only of one week duration. Only 19%

of the programs had a minimum number of cases required with the use of each device.

Pott et al (82) performed a similar survey in 2011 and found that 49% of the American and

Canadian anaesthesiology registrar programs had prescribed airway training programs. This

steady increase in airway training programs over the years shows that there seems to be an

increased appreciation that the teaching of airway management skills forms a fundamental

part in the training of anaesthesiology registrars. This survey also found that simulation

training was used in 68% of the programs, compared with only 12% in the survey by

Hagberg et al (81). Pott et al (82) recommended that by instituting formalised airway

training programs, adverse peri-operative outcomes may be decreased.

Simulation training has shown to be an effective method to ensure skill retention and better

compliance with difficult airway algorithms. Boet et al (83) performed a study in 2011

amongst 38 experienced anaesthetists who participated in a “high-fidelity simulated CICV

scenario” training session. These anaesthetists were then randomised into either the 6

month or 12 month follow-up group. Both groups’ cricothyroidotomy skills improved

significantly from before the training and there were no significant difference between the

two groups’ retention of the skills after either 6 or 12 months. A similar study was

performed by Hubert et al (84) in 2014 amongst 27 anesthesiology registrars. The

participants’ compliance to airway algorithms improved from 63% in the pre-training test to

100% in the post-test and cricothyroidotomy times decreased significantly. The participants

were randomised into 3, 6 or 12 month follow-up groups and there was no significant

increase in the time to perform a cricothyroidotomy between the three groups. Both these

studies agree that cricothyroidotomy skills can be maintained for up to one year if it was

taught in a “high fidelity simulated” environment.

An example of a formal airway teaching program for anaesthesiology trainees was published

by Dunn et al (85) from the Tufts University School of Medicine in 2004. Their curriculum

consists of a total of three months of airway training. The training consists of a series of

36

lectures, prescribed reading material and certain required practical skills. The registrars are

required to do a minimum number of successful intubations with the fibreoptic scope,

Bullard laryngoscope and the ILMA™. They also have uniformly stocked airway trolleys that

are readily available in emergency situations. The level of comfort in their department in

performing and teaching a fibreoptic intubation improved from 62% to 92% after this airway

rotation was instituted. More than 90% of the consultants in the department also reported

that the resident rotation improved their own airway skills, showing that a formal teaching

program can be of benefit to the whole department.

2.9 Summary

In this chapter the literature review was presented. In the next chapter the research

methodology will be discussed.

37

CHAPTER 3: Research methodology

3.1 Introduction

In this chapter the problem statement, aim and objectives, ethical considerations, research

methodology, data analysis and the validity and reliability of the study are discussed.

3.2 Problem statement

The CICV scenario is a rare occurrence but can lead to significant morbidity and mortality if

not managed appropriately (2, 16). It has been shown internationally that anaesthetists

generally lack knowledge of difficult airway algorithms or fail to employ them in emergency

situations (4). Although many advances have been made in airway management, adverse

respiratory events still form a large part of malpractice claims (14, 17, 18). Medical officers

and registrars working in the Department of Anaesthesiology at Wits are occasionally in a

situation where senior help is not immediately available, should an airway emergency

present itself. The preferences, experience and level of comfort of these anaesthetists to

manage difficult intubations and CICV situations and use available airway adjuncts have not

been previously described.

3.3. Aim and objectives

3.3.1 Aim

The aim of the study was to describe the preferences, experience and level of comfort of

anaesthetists in the Wits Department of Anaesthesiology in managing difficult intubation

and CICV scenarios.

3.3.2 Objectives

The objectives of this study were to:

describe the knowledge of anaesthetists regarding the location of the “difficult

airway trolley” in the various hospitals affiliated to Wits;

describe the preferences of anaesthetists with different airway devices and

techniques when faced with a difficult intubation or CICV scenario; and

38

describe the experience and comfort level of anaesthetists when managing a difficult

airway or CICV scenario.

3.4 Ethical considerations

Approval to conduct the study was obtained from the Human Research Ethics Committee

(Medical) (Appendix A) and the Post Graduate Committee (Appendix B) of the University of

the Witwatersrand.

Participants were invited to take part in the study at academic meetings. An information

sheet (Appendix C) and a questionnaire (Appendix D) were provided to those who agreed to

participate. Participation was voluntary and refusal to participate did not have any negative

sequelae. Completion of the questionnaire implied consent.

Anonymity and confidentiality were ensured as no identifying information was requested

from participants. Questionnaires were distributed in a group setting and after completion

were immediately placed in sealed data collection boxes by the participants. Only the

researcher and supervisors had access to the raw data.

Data will be stored securely for six years after completion of the study.

This study was conducted according to the principles of the Declaration of Helsinki (19) and

the South African Guidelines for Good Clinical Practice (20).

3.5 Research methodology

3.5.1 Research design

A prospective, contextual, descriptive research design was followed in this study. In a

prospective study, variables that occur over the course of the study are measured, as in the

case of this study (86). A contextual study is one which is performed in a specific group or

population. De Vos et al (87) defined this as a “small-scale world” or “micro” research. The

“small-scale world” in this study is the Department of Anaesthesiology.

According to Brink et al (86), descriptive research aims to provide information from a

representative sample of a certain population, in a field where data is still lacking, without

trying to determine a “cause-effect relationship”. Burns and Grove (88) stated that it may be

39

used to “develop theory, identify problems with current practice, make judgments, or

determine what others in similar situations are doing.” This study describes the preferences,

experience and comfort level of anaesthetists in the Department of Anaesthesiology in

managing difficult intubations and CICV scenarios.

3.5.2 Study population

The study population consists of anaesthetists working in the Department of

Anaesthesiology.

3.5.3 Study sample

Sample method

In this study a convenience sampling method was used. According to Endacott and Botti (89)

convenience sampling is a form of non-random sampling where the most readily accessible

individuals are included in the study. Questionnaires for this study were distributed at all

the Wits affiliated hospitals during academic meetings, as well as at combined departmental

meetings during the study period, in order to reach the largest sample possible.

Sample size

The department consists of 22 medical officers, 112 registrars and 74 consultants.

Questionnaires were administered to the entire accessible population. A response rate of

60% was considered as acceptable, but a response rate of 80% was targeted.

Inclusion and exclusion criteria

All available anaesthetists working in the Wits Department of Anaesthesiology willing to

participate in the study were included.

Exclusion criteria in this study were:

interns rotating in the department;

anaesthetists that were on annual or sick leave during the study period; and

questionnaires that were returned blank were excluded from the data analysis but

were used to determine the response rate.

40

3.5.4 Data collection

Development of a questionnaire

An extensive review of the literature was done and a questionnaire developed by Wong et

al (16) in 2005 was identified as appropriate for this study. In the original study the authors

developed a survey to determine the preferences of Canadian anaesthesiologists in difficult

intubation and CICV scenarios. Permission was obtained from Wong, via e-mail

correspondence, to adapt the questionnaire for use in this study (Appendix E). The

questionnaire was adapted for local use and validated by four airway management experts

in the Department of Anaesthesiology, thereby ensuring content and face validity of the

questionnaire.

The self-administered questionnaire (Appendix D) consisted of two sections.

Section 1 included demographic data of the participant, namely:

gender

professional designation

years of anaesthetic experience

recent attendance of an airway workshop

use of airway algorithms and/or guidelines.

Section 2 consists of questions regarding:

knowledge of the location of the difficult airway trolleys at the various Wits affiliated

hospitals

preference, experience and comfort level with different airway devices when

managing a difficult intubation

preference, experience and comfort level when managing a CICV scenario.

Data collection process

Data was collected by distributing questionnaires at academic meetings at the various

hospitals as well as at combined departmental meetings during the months of June to

December 2015. At the start of the meeting, the researcher asked permission from the

convenor to address the potential participants. The researcher was present during

41

completion of questionnaires to assist with any queries. Before distribution, questionnaires

were numbered to keep track of completed questionnaires and to calculate a response rate.

After brief introduction by the researcher to clarify the aim and objectives of the study,

anaesthetists had the opportunity to decide whether they wanted to participate in the

study. Those who agreed to do so received an information letter (Appendix C) along with

the questionnaire (Appendix D). After completion of the questionnaire, the participant

placed it into a sealed data collection box.

3.6 Data analysis

Data was captured onto spread sheets using Microsoft Excel® 2010 and analysed using

GraphPad InStat® in consultation with a bio-statistician. Descriptive and inferential statistics

were used to analyse the data. Categorical variables were described using frequencies and

percentages. A sub-analysis was done to compare the level of comfort to the demographic

variables using Fisher’s exact tests. A p-value of <0.05 was considered statistically

significant.

3.7 Validity and reliability of the study

According to Botma et al (90), validity represents the degree to which measurements

represent the true value. To attain validity, the appropriate study design and data collection

techniques should be used. (90)

Reliability refers to consistency of the measure achieved. The measuring instrument should

therefore be able to produce the same results under different circumstances. (90)

The following measures ensured validity and reliability of this study:

a validated questionnaire that was adapted for local use was used for data

collection;

the adapted questionnaire was validated by four airway management experts;

the researcher was available to answer questions while questionnaires were being

completed;

all questionnaires were completed under the same circumstances;

42

all questionnaires were completed anonymously and placed in sealed data collection

boxes;

10% of data entries were checked for accuracy of entry; and

data was analysed in consultation with a bio-statistician.

3.8 Summary

In this chapter the research methodology was presented. In the next chapter the results of

the study are reported and discussed.

43

CHAPTER 4: Results and discussion

4.1 Introduction

In this chapter, the results of this study are presented, in keeping with the objectives of the

study, and the discussion thereof follows. The objectives of this study were to:

describe the knowledge of anaesthetists regarding the location of the “difficult

airway trolley” in the various hospitals affiliated to Wits;

describe the preferences of anaesthetists with different airway devices when

faced with a difficult intubation or CICV scenario; and

describe the experience and comfort level of anaesthetists when managing a

difficult airway or CICV scenario.

4.2 Sample realisation

Data was collected at departmental meetings between June and December 2015. The

department consists of 208 anaesthetists. At the time of data collection, it was determined

that approximately 42 (20%) anaesthetists will not be available due to leave or rotations out

of town, leaving a total number of 166 available. A total of 132 (80% of available

anaesthetists) was targeted for this study, but 100 (60%) was deemed adequate. Of the 135

questionnaires distributed 126 (93%) were returned. This was 76% of the targeted number

of anaesthetists.

4.3 Results

Percentages are rounded off to the first decimal place, and may not add up to exactly 100%,

as with questions where participants could choose more than on option. The Likert scale

data regarding the comfort level was converted to “comfortable” and “uncomfortable”, as

was done in the original study by Wong et al (16). The group that selected “equivocal” was

excluded as it did not fit either category. The full break-down of the Likert scale data is

shown in Appendix F. Subanalysis was done to compare the level of comfort with use of

different airway devices between the consultants and registrars/MO’s . A sample size was

not calculated to determine if these comparisons would be adequately powered.

44

4.3.1 Demographics

The majority, 80 (63.5%) participants were female, 64 (50.8%) were registrars and 70

(55.6%) had 1 to 5 year of anaesthetic experience. Only 28 (22.2%) had never attended an

airway workshop and of those who had, most attended less than a year ago. The majority,

103 (81.7%) participants use published algorithms and/or guidelines when managing a

difficult airway and the ASA guidelines are the most widely used. The demographics of the

participants are shown in Table 4.1.

Table 4.1 Demographics of participants

Demographic Number Percentage

n=126 (n) (%)

Gender

Male 46 36.5

Female 80 63.5

Professional designation

Consultant 47 37.3

Registrar 64 50.8

Medical officer 15 11.9

Years of experience

Less than 1 8 6.3

1-5 years 70 55.6

6-10 years 30 23.8

11-20 years 8 6.3

>20 8 6.3

No data 2 1.6

Attendance of an airway workshop

Never 28 22.2

<1 year ago 48 38.1

1-2 years ago 38 30.2

2-4 years ago 7 5.6

>4 years ago 5 4.0

Use of guidelines

No guidelines used 23 18.3

Unsure of the name 13 10.3

ASA 50 39.7

DAS 21 16.7

Vortex 13 10.3

Other 6 4.8

45

4.3.2 Objective: to describe the knowledge of anaesthetists regarding the location

of the “difficult airway trolley” in the various hospitals

A total of 111 (88.1%) participants know the location of the difficult airway trolley, but 43

(38.7%) stated that the trolley is not easily accessible in case of an unanticipated difficult

airway. This is shown in Figure 4.1. One participant did not answer the question.

Figure 4.1 Overall knowledge of location of the difficult airway trolley

When looking at the different hospitals, 5 (14.3%) of the participants from CMJAH and 3

(12.5%) from HJH/RMMCH do not know the location of the difficult airway trolley, while at

CHBAH the proportion is lower, with 6 (9.2%) not knowing. Of the participants who know

the location of the trolley, 17 (56.7%) from CMJAH and 24 (40.7%) from CHBAH are of the

opinion that it is not readily accessible in an emergency situation. At HJH/RMMMC the

number is lower as only 2 (9.5%) feel that the trolley is not readily accessible in an

emergency. See table 4.2 for the full breakdown of these results.

Knowledge of location of the difficult airway trolley (n=125)

No

n=14 (11.2%)

Yes

n=111 (88.1%)

Not easily accessible in an emergency n=43 (38.7%)

Easily accessible in an emergency

n=68 (61.3%)

46

Table 4.2 Knowledge of the location of the difficult airway trolley at different

hospitals

Hospital

Participants

per

hospital

n (%)

Location

unknown

n (%)

Location known

n (%)

Total

Accessible

in

emergency

Not

accessible in

emergency

CMJAH 35 (27.8) 5 (14.3) 30 (85.7) 13 (43.3) 17 (56.7)

CHBAH 65 (51.6) 6 (9.2) 59 (90.8) 35 (59.3) 24 (40.7)

HJH/RMMCH 24 (19.0) 3 (12.5) 21 (87.5) 19 (90.5) 2 (9.5)

WDGMC 1 (0.8) 0 1 (100) 1 (100) 0

4.3.3 Objective: to describe the preferences of anaesthetists for different airway

devices

The majority, 92 (73%) participants chose the videolaryngoscope as a first choice device

when facing a difficult airway scenario. The predominant second choice devices were the

flexible fibre-optic scope, chosen by 52 (41.2%) and the intubating laryngeal mask, chosen

by 48 (38.1%). The device preference for managing a difficult airway is illustrated in Figure

4.2. No one chose the retrograde wire or rigid bronchoscope as either their first or second

option.

Figure 4.2 Device preferences for managing a difficult airway

0

10

20

30

40

50

60

70

80

90

100

Nu

mb

er

of

par

tici

pat

ns

Airway device

First choice

Second choice

47

The most popular choice for managing an airway in a CICV scenario is using an IV cannula to

perform a cricothyroidotomy, with 47 (37.3%) participants selecting this as their first choice.

As a second choice, 41 (32.5%) chose a tracheostomy by the surgeon. The open surgical

method and tracheostomy by the anaesthetist were the least popular choices overall. Figure

4.3 shows the device preference in a CICV scenario.

Figure 4.3 Preferences when managing a CICV scenario

4.3.4 Objective: to describe the experience and comfort level of anaesthetists

when managing a difficult airway or CICV scenario

Experience and comfort level of anaesthetists when managing a difficult airway

scenario

The videolaryngoscope is the most widely used alternative airway device, with 111 (88.1%)

of participants having used it in asleep patients. The fibre-optic scope has also been used by

the majority of participants in either an awake and/or an asleep patient. The retrograde

wire set, the optical stylet and the rigid bronchoscope are all devices with which the

majority of participants had no experience. These results are shown in Table 4.3. With this

question, the participants could choose more than one option thus percentages may add up

to more than 100%.

0

5

10

15

20

25

30

35

40

45

50

Nu

mb

er

of

par

tici

pan

ts

Device or method

First choice

Second choice

48

Table 4.3 Experience of anaesthetists with different airway devices used for difficult

airway scenarios

Device

Never

used

n (%)

Used n (%)

Total

n (%)

Mannequin

n (%)

Awake

n (%)

Asleep

n (%)

Flexible fibreoptic

scope 13 (10.3) 113 (89.7) 26 (20.6) 82 (65.1) 98 (77.7)

Intubating laryngeal

mask 25 (19.8) 101 (80.2) 42 (33.3) 2 (1.6) 68 (54)

Videolaryngoscope 6 (4.8) 120 (95.2) 25 (19.8) 10 (7.9) 111 (88.1)

Retrograde wire set 79 (62.7) 47 (37.3) 41 (32.5) 0 (0) 6 (4.8)

Optical stylet 75 (59.5) 51 (40.4) 42 (33.3) 0 (0) 15 (11.9)

Rigid bronchoscope 93 (73.8) 33 (26.2) 10 (7.9) 1 (0.8) 26 (20.6)

Figure 4.4 shows the percentage of participants that are comfortable with each of the

different devices. The overall percentages of participants that are comfortable using the

devices are shown, as well as the percentages of consultants and registrars/MO’s. The

number of participants that have experience with each of the different devices (as shown in

Table 4.3) corresponds well with the percentage of participants that are comfortable with

the different devices.

Figure 4.4 Participants comfortable with different airway devices used for difficult

airway scenarios

0

10

20

30

40

50

60

70

80

90

100

Par

tici

pan

ts c

om

fort

able

(%

)

Airway device

Overall

Consultants

Registrars/MO's

49

Figure 4.5 shows the percentage of participants that are uncomfortable with each of the

different devices. The group that selected “equivocal” were not included, thus the

comfortable and uncomfortable groups will not add up to 100%.

Figure 4.5 Participants uncomfortable with different airway devices used for difficult

airway scenarios

A sub-analysis was done to compare the level of comfort with use of different airway

devices between the consultants and registrars/MO’s, using a Fisher’s exact test. This is

shown in Table 4.4. There was a statistically significant difference (p-value <0.05) in the level

of comfort between the consultant and registrar/MO’s groups with all the devices except for

the videolaryngoscope.

Table 4.4 Comparison of the level of comfort of consultants vs registrars/MO’s with

the use of different airway devices

Airway device Consultants Comfortable/

Uncomfortable

Registrars/MO’s Comfortable/

Uncomfortable p-value

Awake fibreoptic intubation 30/11 19/46 p=0.0001

Asleep fibreoptic intubation 37/6 35/24 p=0.0041

Intubating laryngeal mask 29/6 28/22 p=0.0108

Videolaryngoscope 42/1 67/9 p=0.0921

Retrograde wire set 4/30 1/65 p=0.0444

Optical stylet 9/19 4/52 p=0.0077

Rigid bronchoscope 8/26 3/60 p=0.0146

0

10

20

30

40

50

60

70

80

90

Par

tici

pan

ts u

nco

mfo

rtab

le (

%)

Airway device

Overall

Consultants

Registrars/MO's

50

Experience and comfort level of anaesthetists when managing a CICV scenario

Sixty-three (50%) of the participants have experienced a CICV scenario in clinical practice,

but only six (4.8%) have had more than two CICV experiences, as depicted in Table 4.5.

Table 4.5 Experience of CICV scenario

Most participants have experience with performing a cricothyroidotomy on a mannequin,

with an intra-venous (IV) cannula, a percutaneous dilation kit and/or the guidewire. The

open surgical method and the performance of a tracheostomy were techniques with which

the majority of participants had no experience with. Very few of the participants had

experience with any of the devices or techniques on a patient. These results are shown in

Table 4.6.

Table 4.6 Experience of anaesthetists with different airway devices used for CICV

scenarios

Device Never used

n (%)

Used n (%)

Total n (%) Mannequin

n (%)

Patient

n (%)

IV cannula 30 (23.8) 96 (76.2) 85 (67.5) 14 (11.1)

Percutaneous dilation kit 43 (34.1) 83 (65.9) 78 (61.9) 5 (4)

Guide wire 39 (31) 87 (69.0) 85 (67.5) 3 (2.4)

Open surgical method 79 (62.7) 47 (37.3) 42 (33.3) 6 (4.8)

Tracheostomy 101 (80.2) 25 (19.8) 14 (11.1) 11 (8.7)

Figure 4.6 shows the percentage of participants comfortable with using the different devices

or techniques used in a CICV scenario. The IV cannula was the device with which most

participants felt comfortable, even though the overall percentage of participants

comfortable was only 34.9%. In the consultant group, 55.3% were comfortable with using

the IV cannula, while only 22.8% of the registrars/MO’s were comfortable.

Experience of CICV scenario Number (%)

Never 63 (50)

1-2 times 57 (45.2)

>2 times 6 (4.8)

51

Figure 4.6 Participants comfortable with equipment used for cricothyroidotomy/

surgical airway in CICV scenario

Figure 4.7 shows the percentage of participants that are uncomfortable with each of the

different devices or methods used for a CICV scenario. Again, the group that selected

“equivocal” were not included, thus the comfortable and uncomfortable groups will not add

up to 100%. The open surgical method and the tracheostomy are the two methods with

which most participants felt uncomfortable with.

Figure 4.7 Participants uncomfortable with equipment used for cricothyroidotomy/

surgical airway in CICV scenario

0

10

20

30

40

50

60

IV cannnula Percutaneousdilatation kit

Guide wire Open surgicalmethod

Tracheostomy

Par

tici

pan

ts c

om

fort

able

(%

)

Devices or techniques used for CICV scenario

Overall

Consultants

Registrars/MO's

0

10

20

30

40

50

60

70

80

90

100

IV cannula Percutaneousdilatation kit

Guide wire Open surgicalmethod

Tracheostomy

Par

tici

pan

ts u

nco

mfo

rtab

le (

%)

Devices or techniques used for CICV scenario

Overall

Consultants

Registrars/MO's

52

A sub-analysis was done to compare the level of comfort with use of different devices and

methods between the consultants and registrars/MO’s, using a Fisher’s exact test. This is

shown in Table 4.7. There was a statistically significant difference (p-value <0.05) in the level

of comfort between the consultant and registrar/MO’s groups with all the devices except for

the tracheostomy.

Table 4.7 Comparison of the level of comfort of consultants vs registrars/MO’s with

the use of different airway devices

Airway device Consultants

Comfortable/Uncomfortable

Registrars/MO’s

Comfortable/Uncomfortable p-value

IV cannula 26/13 18/35 p=0.0029

Percutaneous dilation

kit 13/16 12/45 p=0.0265

Guide wire 14/17 13/47 p=0.0290

Open surgical method 7/33 2/65 p=0.0130

Tracheostomy 4/38 2/72 p=0.1873

4.4 Discussion

The aim of the study was to describe the preferences, experience and level of comfort of

anaesthetists in the Wits Department of Anaesthesiology in managing difficult intubation

and CICV scenarios.

Several algorithms and guidelines for management of the difficult airway have been

formulated by national societies as well as by local institutions (2, 5, 7, 11). The majority of

participants, 103 (81.7%) in my study stated that they use described guidelines when

managing a difficult airway scenario. The most common choice was the ASA guidelines,

which was chosen by 50 (39.7%) participants. This was an open ended question, but the ASA

guidelines were given as an example, which might have led to participants stating it as their

choice. The other popular choices were the DAS guidelines, chosen by 21 (16.7%) and the

Vortex approach, chosen by 13 (10.3%). The most recent SASA airway guidelines that were

published in 2014 include the ASA difficult airway algorithm, the DAS guidelines as well and

the Vortex approach, and the authors do not recommend one guideline above the other

(65). A critique of the ASA as well as the DAS algorithms however, is that they are

53

complicated and allow for too many management choices at each stage, making it difficult

to recall and apply in an emergency situation (2, 7). The Vortex approach serves as a

straightforward “cognitive aid” to encourage a structured approach rather than progression

through a linear algorithm when dealing with a difficult airway (2). This approach has been

discussed and encouraged at airway workshops in our department.

Fourteen (11.2%) participants did not know the location of the difficult airway trolley at the

hospitals where they were rotating. What was also of concern is that of the participants who

did know the location, 43 (38.7%) were of the opinion that the trolley is not easily accessible

in case of an airway emergency. This was shown to be problem in other centres as well. An

example is a simulation study by Green (4) in a large teaching hospital in Glasgow, UK that

showed that 62.9% of anaesthetists could not locate either of the two difficult airway

trolleys in the theatre complex.

CMJAH had the highest percentage of participants, 17 (56.7%) who felt that the airway

trolley is not accessible in an airway emergency. The airway trolley and videolaryngoscopes

in the main theatre complex at this hospital are kept in the anaesthetic department behind

an access controlled gate. At the HJH and RMMCH the numbers were better with only two

(9.2%) of participants at these hospitals stating that the trolley is not accessible in an

emergency. At these hospitals, the difficult airway trolleys are kept in the recovery rooms.

The videolaryngoscopes at these hospitals (HJH and RMMCH) are however locked away and

not easily accessible after hours without a consultant being present, while at the other

hospitals they are accessible 24 hours a day.

In the difficult airway scenario, the videolaryngoscope was the most popular device and was

chosen by 92 (73%) participants as their first choice. A possible explanation for this is that

videolaryngoscopes are available at all of the Wits affiliated hospitals and their use is

encouraged for the management of anticipated difficult airways. Almost all participants, 120

(95.2%) have used the videolaryngoscope and this was reflected in the large percentage

(86.5%) of participants that are comfortable using this device. This was the only difficult

airway device where there were no statistically significant difference in the comfort level

between consultants and registrars (p = 0.0921). The latest DAS guidelines recommend that

all anaesthetists should be competent in using the videolaryngoscope and that it should be

54

immediately available (10). Aziz et al (64) however stated that anaesthetic providers “should

maintain their competency with alternate methods of intubation, especially for patients

with neck pathology.”

At the time of the original study by Wong et al (16) in 2005, videolaryngoscopes were not

widely available yet and only 1.3% of participants chose the Glidescope™ as their first choice

device. The lighted stylet was the most popular first choice in their study and was chosen by

44.5% participants. Even though there are still optical stylets available, it is not a widely

preferred or used device and only 13 (10.3%) participants in my study felt comfortable using

it.

The second choice devices for a difficult airway scenario were similar to the study by Wong

et al (16). When comparing the figures from the two studies, the ILMA™ was chosen by

38.1% in my study vs 32.1% participants in the study by Wong et al (16) and the fibreoptic

scope was chosen by 41.3% vs 40.5% as second choice devices. Even though 80.2% of

participants had experience with the ILMA™, only 61.7% of consultants and 35.4% of

registrars felt comfortable using this device. Separate studies by Kapila et al (41) and later

by Baskett et al (42) showed that there is a learning curve associated with the use of the

ILMA™. It is however recommended as essential equipment for airway rescue. In a review

by Caponas (43) about the ability of the ILMA™ to facilitate blind intubation, the success

rate of intubation was 95.7% in a total of 1110 patients.

The technique of fibreoptic intubation has become the “gold-standard” for awake

intubation in cases where a difficult airway is expected, but requires practice and skill to be

used effectively (31). Even though fibreoptic intubations have been done by 89.7% of

participants in my study, only 38.9% feel comfortable performing it on an awake patient and

57.1% in an asleep patient. The registrars and medical officers were significantly less

comfortable with awake (p=0.0001) and asleep (p=0.0041) fibreoptic intubations than the

consultants.

Similar to the findings of Wong et al (16), the retrograde wire and the rigid bronchoscope

are devices with which most participants had no experience and this is reflected by the low

numbers in both the consultant and registrar groups that prefer these devices and are

comfortable with using them.

55

Fifty percent of participants in my study had been involved in a CICV scenario, with 46.2%

having had one or two CICV experiences and 4.8% participants having had more than two.

These numbers are slightly lower but similar to the numbers in the study by Wong et al (16).

The cricothyroidotomy by IV cannula was the preferred first choice device to establish an

infraglottic airway in a CICV scenario by the majority of participants, 47 (37.3%). A total of

96 (76.2%) participants have experience with this technique (although mostly only on a

mannequin). Wong et al (16) had similar findings and they believe that this technique is

preferred because it is readily available and the least complicated. The use of an IV cannula

is however discouraged in the literature as it is not kink-resistant, it does not protect the

patient from aspiration, does not provide effective ventilation, requires a special

attachment for jet ventilation and is associated with a high incidence of barotrauma (1).

Several different large bore (>4 mm internal diameter) cannula cricothyroidotomy sets have

been developed and are available commercially and the wide choice makes it difficult to

know which device is most appropriate to use in an emergency (71). Two non-surgical

techniques include the “cannula-over-trocar” and the guide wire (or Seldinger) technique,

which is a technique that most anaesthetists are familiar with. More than 60% of

participants had experience with both of these techniques on mannequins but only 19.8%

and 21.4% of participants felt comfortable with these two techniques, respectively.

The open surgical method and the tracheostomy were the least popular choices for airway

management in a CICV scenario. After the findings of NAP4 (27), the latest DAS guidelines

recommend the use of the open surgical technique to secure the airway in a CICV scenario

(10). Only 37.3% of participants had experience in performing an open surgical airway

(mostly on a mannequin) and only 7.1% felt comfortable with this technique. There was

again a statistically significant (p=0.013) difference between the level of comfort of

consultants (of which 14.2% are comfortable) and registrars/MO’s (of which only 2.5% are

comfortable) with this technique.

The benefit of formal airway training is evident and therefore an increasing number of

registrar training programs have implemented formal airway rotations as part of their

curriculum (80-82). Even though airway workshops are held in the Wits Department of

Anaesthesiology on a bi-annual basis, there is no formal airway teaching program and

56

registrars are not formally assessed on their techniques when using different airway

devices. Simulation training has shown to be an effective method to ensure skill retention

and better compliance with difficult airway algorithms. Different studies agree that

cricothyroidotomy skills can be maintained for up to one year if it was taught in a “high

fidelity simulated” environment (83, 84). At this stage, no “high fidelity” simulation training

has been done in our department to teach cricothyroidotomy skills and only occasional

demonstrations and practice on mannequins are done at airway workshops. This study has

shown that there is much room for improvement in the field of airway training in the

department.

4.5 Summary

In this chapter the results and discussion were presented. The next chapter contains a

summary of the study, the limitations, recommendations and a conclusion.

57

CHAPTER 5: Study summary, limitations, recommendations

and conclusion

5.1 Introduction

In this chapter a summary of this study, limitations, recommendations for changes in

practice, future research and a conclusion will be presented.

5.2 Study summary

5.2.1 Aim

The aim of the study was to describe the preferences, experience and level of comfort of

anaesthetists in the Wits Department of Anaesthesiology in managing difficult intubation

and CICV scenarios.

5.2.2 Objectives

The objectives of this study were to:

describe the knowledge of anaesthetists regarding the location of the “difficult

airway trolley” in the various hospitals affiliated to Wits;

describe the preferences of anaesthetists with different airway devices and

techniques when faced with a difficult intubation or CICV scenario; and

describe the experience and comfort level of anaesthetists when managing a difficult

airway or CICV scenario.

5.2.3 Methodology

A prospective, contextual, descriptive research design was followed and a convenience

sampling method was used. The study population consisted of the anaesthetists working in

the Wits Department of Anaesthesiology. An extensive review of the literature was done

and a questionnaire developed by Wong et al (16) in 2005 was identified as appropriate for

this study. The questionnaire was adapted for local use and validated by four airway

management experts in the Department of Anaesthesiology, thereby ensuring content and

face validity of the questionnaire. Questionnaires (Appendix D) were distributed during

58

academic meetings, as well as at combined departmental meetings from June to December

2015. Data was captured onto spread sheets using Microsoft Excel® 2010 and analysed

using GraphPad InStat®. Descriptive and inferential statistics were used to analyse the data.

5.2.4 Results

Of the 126 participants, it was found that a total of 111 (88.1%) participants knew the

location of the difficult airway trolley, but 43 (38.8%) stated that the trolley is not easily

accessible in case of an unanticipated difficult airway.

The majority, 92 (73%) participants preferred the videolaryngoscope as a first choice device

when facing a difficult airway scenario. The predominant second choice devices were the

flexible fibre-optic scope, chosen by 52 (41.3%) and the intubating laryngeal mask, chosen

by 48 (38.1%). The videolaryngoscope was the most widely used alternative airway device,

with 111 (88.1%) participants having used it in asleep patients. The retrograde wire set, the

optical stylet and the rigid bronchoscope were all devices with which the majority of

participants had no experience. The number of participants who had experience with the

different devices corresponded well with the percentage of participants who were

comfortable with the different devices.

The most popular choice, chosen by 47 (37.3%) participants for managing an airway in a

CICV scenario, was to use an IV cannula to perform a cricothyroidotomy. The IV cannula was

also the device with which most participants felt comfortable even though the overall

number comfortable was only 44 (34.9%). As a second choice, 41 (32.5%) chose a

tracheostomy by the surgeon. The open surgical method and tracheostomy by the

anaesthetist were the least popular choices overall and most participants felt

uncomfortable with these methods. Sixty-three (50%) of the participants have experienced

a CICV scenario, but only 6 (4.8%) have had more than two CICV experiences.

5.3 Limitations

The following limitations were identified in this study.

This study was contextual in nature and therefore the results of this study may not be

extrapolated to other academic anaesthetic departments or private practice.

59

Convenience sampling was used. This sampling method, although often used, can lead

to bias as some elements might be over- or underrepresented (86).

There is no standardisation of airway equipment between the different study hospitals.

The participants’ device preference and comfort level could therefore have been

influenced by the devices they had available.

5.4 Recommendations

5.4.1 Clinical practice

The following recommendations are proposed for clinical practice.

Difficult airway trolleys and equipment should be standardised at the various Wits

affiliated hospitals.

The airway trolley should be easily accessible at all hospitals and the location thereof

should be regularly communicated to new and existing staff.

A compulsory airway teaching program should be implemented in our department,

based on published data regarding airway rotations in other anaesthetic

departments, as part of registrar training.

“High fidelity” simulation training should be implemented in our department,

especially for the acquisition of cricothyroidotomy skills.

Formal assessment of registrars’ airway management skills with the use of different

devices and techniques should be implemented in our department.

5.4.3 Further research

The following recommendations are proposed for further research.

Similar studies could be performed in other anaesthetic departments in South Africa

to determine where deficiencies in skills and experience lies, and whether further

training is required.

A follow-up study could be done after the implementation of an airway teaching

program, to determine whether formal airway training improves the comfort level of

anaesthetists in our department.

60

5.5 Conclusion

In conclusion, this study found that there is much room for improvement in airway training

in our department. The location of the difficult airway trolley is not known by all

anaesthetists in the department and many are of the opinion that it is not readily available

in an emergency situation. Most anaesthetists have used and prefer the videolaryngoscope

for the management of a difficult airway and are comfortable using it. There is however a

significant difference in the comfort level of consultants and registrars with the use of all of

the other devices used in a difficult airway scenario. In a CICV scenario, most anaesthetists

prefer the IV cannula as a first choice to perform a cricothyroidotomy. Even though the

open surgical method is the recommended method in the literature with the lowest

complication and failure rate, the majority of anaesthetists have no experience with this

method, even on a mannequin, and most feel uncomfortable performing this method.

61

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44. Ocker H, Wenzel V, Schmucker P, Steinfath M, Dörges V. A comparison of the laryngeal tube with the laryngeal mask airway during routine surgical procedures. Anesthesia & Analgesia. 2002;95:1094-7. 45. Cook T, McCormick B, Asai T. Randomized comparison of laryngeal tube with classic laryngeal mask airway for anaesthesia with controlled ventilation. British Journal of Anaesthesia. 2003;91(3):373-8. 46. Asai T, Shingu K. The laryngeal tube. British Journal of Anaesthesia. 2005;95(6):729-36. 47. Cook T, Lee G, Nolan J. The ProSeal™ laryngeal mask airway: a review of the literature. Canadian Journal of Anaesthesia. 2005;52(7):739-60. 48. Cook T, Silsby J, Simpson T. Airway rescue in acute upper airway obstruction using a ProSealTM Laryngeal mask airway and an Aintree CatheterTM: a review of the ProSealTM Laryngeal mask airway in the management of the difficult airway. Anaesthesia. 2005;60:1129-36. 49. Eschertzhuber S, Brimacombe J, Hohlrieder M, Keller C. The Laryngeal Mask Airway Supreme™ – a single use laryngeal mask airway with an oesophageal vent. A randomised, cross-over study with the Laryngeal Mask Airway ProSeal™ in paralysed, anaesthetised patients. Anaesthesia. 2009;64:79-83. 50. Van Zundert A, Brimacombe J. The LMA Supreme™- a pilot study. Anaesthesia. 2008;63:209-10. 51. Wong D, Yang J, Jagannathan N. Brief review: the LMA Supreme™ supraglottic airway. Canadian Journal of Anaesthesia. 2012;59:483-93. 52. Verghese C, Ramaswamy B. LMA-SupremeTM—a new single-use LMATM with gastric access: a report on its clinical efficacy. British Journal of Anaesthesia. 2008;101(3):405-10. 53. López A, Valero R, Brimacombe J. Insertion and use of the LMA SupremeTM in the prone position. Anaesthesia. 2010;65:154-7. 54. Sharma V, Verghese C, McKenna P. Prospective audit on the use of the LMA-SupremeTM for airway management of adult patients undergoing elective orthopaedic surgery in prone position. British Journal of Anaesthesia. 2010;105(2):228-32. 55. Pearson D, Young P. Use of the LMA-SupremeTM for airway rescue. Anesthesiology. 2008;109:356-7. 56. Gatward J, Cook T, Seller C, Handel J, Simpson T, Vanek V, et al. Evaluation of the size 4 i-gelTM airway in one hundred non-paralysed patients. Anaesthesia. 2008;63:1124-30. 57. Ragazzi R, Finessi L, Farinelli I, Alvisi R, Volta C. LMA SupremeTM vs i-gelTM - a comparison of insertion success in novices. Anaesthesia. 2012;67:384-8. 58. Mihai R, Knottenbelt G, Cook T. Evaluation of the revised laryngeal tube suction: the laryngeal tube suction II in 100 patients. British Journal of Anaesthesia. 2007;99(5):734-9. 59. Vézina D, Lessard M, Bussières J, Topping C, Trépanier C. Complications associated with the use of the Esophageal-Tracheal Combitube. Canadian Journal of Anaesthesia. 1988;45(1):76-80. 60. Uchida T, Hikawa Y, Saito Y, Yasuda K. The McCoy levering laryngoscope in patients with limited neck extension. Canadian Journal of Anaesthesia. 1997;44(6):674-6. 61. Chrisholm D, Calder I. Experience with the McCoy laryngoscope in difficult laryngoscopy. Anaesthesia. 1997;52:896-913. 62. Healy D, Maties O, Hovord D, Kheterpal S. A systematic review of the role of videolaryngoscopy in successful orotracheal intubation. BMC Anesthesiology [Internet]. 2012; 12(32). 63. Bein B, Yan M, Tonner P, Scholz J, Steinfath M, Dörges V. Tracheal intubation using the Bonfils intubation fibrescope after failed direct laryngoscopy. Anaesthesia. 2004;59:1207-9. 64. Aziz MF, Healy D, Kheterpal S, Fu RF, Dillman D, Brambrink AM. Routine clinical practice effectiveness of the Glidescope in difficult airway management: An analysis of 2,004 Glidescope intubations, complications, and failures from two institutions. Anesthesiology. 2011;114(34-41).

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Appendix A: Ethics approval

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Appendix B: Postgraduate committee approval

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Appendix C: Participant’s information sheet

Dear Colleague,

Hello, my name is Lize, and I am a registrar in the Wits Department of Anaesthesiology. I am conducting a

study as part of my MMed, entitled, “The preferences, experience and level of comfort of anaesthetists in

managing difficult intubation and ‘cannot intubate, cannot ventilate’ scenarios” and would like to invite you to

participate. This study has been approved by the Post-graduate Committee and the Human Research Ethics

Committee (Medical) (M150105) of the University of the Witwatersrand.

This study aims to describe the preferences, experience and comfort level of all anaesthetists in the

department to manage an unanticipated difficult airway, and a “cannot intubate, cannot ventilate” (CICV)

scenario. This is a rare situation in anaesthetic practice, but has devastating consequences if not managed

appropriately. Anaesthetists working in this department are occasionally in a situation where senior help is not

immediately available, should an airway emergency occur. It is not known whether anaesthetists in the

Department of Anaesthesiology at Wits have the necessary experience and comfort to manage a CICV

scenario. This will be determined by a self-administered questionnaire.

Participation in this study is voluntary and consent will be implied on completion of this questionnaire. All

information will be collected anonymously as there will be no personal identifiers on the questionnaire.

Numbering of the questionnaire is for practical purposes only, to prevent replication when capturing data. If

you choose not to participate, it will not have any negative consequences for you. You can choose to withdraw

from this study at any time.

The questionnaire should not take longer than 10 minutes to complete. Please place your questionnaire into

the sealed box provided. Confidentiality will be ensured as the questionnaires will only be viewed by me and

my supervisors.

No incentives will be provided for completion of the questionnaire. The results will help identify whether

additional airway training is needed in this department and will assist our continued professional

development.

All questions regarding this study can be directed to Lize Buitenweg (researcher) on 073 120 1962 or the Chair

of the Human Research Ethics Committee (Medical) on 011 717 1234.

Thank you for taking the time to read this letter.

Sincerely,

Lize Buitenweg

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Appendix D: Questionnaire

Section 1: Demographics

1. Gender

Male

Female

2. Professional designation

Consultant

Registrar

Medical officer

3. Years of experience in anaesthetics

4. Have you ever attended an airway

workshop?

Yes No

5. If yes to question 4, how long ago did

you attend?

6. Do you use a described

algorithm/guidelines when managing a

difficult airway (eg. the ASA

guidelines)?

Yes No

7. If yes to question 6, please state which

guidelines?

____________________________________________________________________

< 1 year

1-5 years

6-10 years

11-20 years

> 20 years

In the last year

1-2 years ago

2-4 years ago

> 4 years ago

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Section 2: Management of difficult intubation and CICV scenarios

1. At which hospital are you currently working/rotating through?

CMJAH

CHBAH

Wits Donald Gordon Medical Centre

HJH/RMMCH

2. Are you aware of the location of the difficult airway trolley at this hospital?

Yes

No

3. If yes, is this difficult airway trolley easily accessible to you in case of an unanticipated

difficult airway?

Yes

No

4. You have a 65 year old man for elective colonic resection. After induction, you fail

intubation twice with direct laryngoscopy and using an introducer or “bougie”, due to an

“anterior larynx”. You can still mask ventilate. His SpO2 is 98%. You have decided to

move to an alternative device to establish a definitive airway. What would be your first

and second choice devices?

Device First choice (Choose 1) Second choice (Choose 1)

Flexible fibreoptic bronchoscope

Intubating laryngeal mask

Videolaryngoscope

Retrograde wire set

Optical stylet

Rigid bronchoscope

Other, please specify

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5. Have you personally used the following intubation devices/techniques? If so, state if on a mannequin or on a patient.

Device Never used Mannequin Patient

Awake Asleep

Flexible fibreoptic bronchoscope

Intubating laryngeal mask

Videolaryngoscope

Retrograde wire set

Optical stylet

Rigid bronchoscope

6. What is your comfort level using the following devices?

1= Completely uncomfortable 2 = Somewhat uncomfortable 3 = Equivocal

4 = Somewhat comfortable 5 = Very comfortable

Awake fibreoptic intubation 1 2 3 4 5

Asleep fibreoptic intubation 1 2 3 4 5

Intubating laryngeal mask 1 2 3 4 5

Videolaryngoscope 1 2 3 4 5

Retrograde wire set 1 2 3 4 5

Optical stylet 1 2 3 4 5

Rigid bronchoscope 1 2 3 4 5

7. Have you ever been involved in a “can’t intubate, can’t ventilate” (CICV) scenario and if

so, how many times?

Never

1-2 times

3 or more times

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8. You are in a CICV situation and the patient’s SpO2 is less than 50%, you have exhausted

all non-surgical options (including an LMA). You need to perform a surgical airway, what

will your first and second choices be? Assume all devices are available for use.

Device First choice (Choose 1)

Second choice (Choose 1)

Cricothyroidotomy with IV cannula (Jelco)

Cricothyroidotomy with percutaneous dilation kit (needle-over-trocar)

Cricothyroidotomy with guide wire (Seldinger) kit

Cricothyroidotomy by open surgical method

Tracheostomy by anaesthetist

Tracheostomy by surgeon

Other, please specify

9. Have you personally used the following intubation devices/techniques? If so, state if on

a mannequin or on a patient.

Device Never used Mannequin Patient

Cricothyroidotomy with a IV cannula

Cricothyroidotomy with percutaneous

dilation kit (needle-over-trocar)

Cricothyroidotomy with guide wire

(Seldinger) kit

Cricothyroidotomy by open surgical

method

Tracheostomy

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10. What is your level of comfort using the devices/techniques on patients? (circle one)

1= Completely uncomfortable 2 = Somewhat uncomfortable 3 = Equivocal

4 = Somewhat comfortable 5 = Very comfortable

Cricothyroidotomy with a IV

cannula 1 2 3 4 5

Cricothyroidotomy with

percutaneous dilation kit

(needle-over-trocar)

1 2 3 4 5

Cricothyroidotomy with guide

wire (Seldinger) kit 1 2 3 4 5

Cricothyroidotomy by open

surgical method 1 2 3 4 5

Tracheostomy 1 2 3 4 5

Thank you for taking the time to complete this questionnaire!

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Appendix E: Permission to use questionnaire

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Appendix F: Likert scale data

Number of participants selecting different comfort levels with use of difficult airway

devices

Device 1 2 3 4 5 Missing

data

Awake FOI 22 35 19 34 15 1

Asleep FOI 11 19 23 42 30 1

ILMA 6 22 40 46 11 1

Videolaryngoscope 3 7 6 36 73 1

Retrograde wire 66 29 22 4 1 4

Optical stylet 49 22 36 12 1 6

Rigid bronchoscope 66 20 26 8 3 3

Number of participants selecting different comfort levels with use of devices/methods

used in a CICV scenario

Device 1 2 3 4 5 Missing

data

Cricothyroidotomy with a

IV cannula 15 33 32 39 5 2

Cricothyroidotomy with

percutaneous dilation kit

(needle-over-trocar)

29 32 37 21 4 3

Cricothyroidotomy with

guide wire (Seldinger) kit 31 33 31 24 3 4

Cricothyroidotomy by

open surgical method 69 29 15 6 3 4

Tracheostomy 86 24 6 3 3 4

1 = Completely uncomfortable

2 = Somewhat uncomfortable

3 = Equivocal

4 = Somewhat comfortable

5 = Very comfortable